Solutions
Chapter 1
Let’s Warm-up
1. 893: 90 2. 349: 9 3. 864: 800
4. 501: 00 5. 123: 3
Do It Yourself 1A
1. a.
2 thousands 3 hundreds 5 tens 6 ones 2356
b. 4 thousands 1 hundreds 1 tens 1 ones 4111
c.
3 thousands 3 hundreds 4 tens 4 ones 3344
d. 5 thousands 4 hundreds 3 tens 1 ones 5431
2. a. Count the number of beads on each rod.
4 beads at the thousands place
7 beads at the hundreds place
4 beads at the tens place
6 beads at the ones place
So, the number is 4746.
b. Count the number of beads on each rod.
5 beads at the thousands place
6 beads at the hundreds place
2 beads at the tens place
5 beads at the ones place
So, the number is 5625.
c. Count the number of beads on each rod.
5 beads at the thousands place
2 beads at the hundreds place
4 beads at the tens place
1 beads at the ones place
So, the number is 5241.
3. a. 1932 b. 5358
3041
4. a. 1532 - One thousand five hundred thirty-two
b. 3156 - Three thousand one hundred fifty-six
c. 4811 - Four thousand eight hundred eleven
d. 6518 - Six thousand five hundred eighteen
e. 7294 - Seven thousand two hundred ninety-four
f. 8043 - Eight thousand forty-three
5. a. 3215 - Place value = 200; Face value = 2
b. 5362 - Place value = 5000; Face value = 5
c. 7314 - Place value = 4; Face value = 4
d. 6892 - Place value = 90; Face value = 9
e. 8113 - Place value = 8000; Face value = 8
f. 9686 - Place value = 9000; Face value = 9
6. a. Three thousand two hundred forty-five = 3245
b. Five thousand three hundred eighty-six = 5386
c. Seven thousand forty = 7040
d. Six thousand eight = 6008
7. a. 2148 = 2000 + 100 + 40 + 8
b. 4036 = 4000 + 000 + 30 + 6
c. 6105 = 6000 + 100 + 00 + 5
d. 7203 = 7000 + 200 + 00 + 3
e. 8200 = 8000 + 200 + 00 + 0
f. 6566 = 6000 + 500 + 60 + 6
8. Length of NH44 = 4412 km
It can be written in words as four thousand one hundred twelve.
Challenge
1. Value of the thousands place = 1000
The hundreds place has the digit of the largest value - 9
Value of the hundreds place = 900
The tens place digit is 2 less than the hundreds place digit. 9 − 2 = 7. So, value of the tens place = 70
The sum of all the digits is 20. We get
1 + 9 + 7 + ____ = 20
17 + ___ = 20
___ = 20 − 17
___ = 3
= 1 + 9 + 7 + 3 = 20
The year is 1973.
Do It Yourself 1B
1. The numbers ending with 1, 3, 5, 7 and 9 are odd numbers.
Odd numbers: c. 83, d. 91, e. 63, g. 149
The numbers ending with 0, 2, 4, 6 and 8 are even numbers.
Even numbers: a. 36, b. 78, f. 164, h. 348
2. a. 614 < 1700
614 is a 3-digit number and 1700 is a 4-digit number
A 4-digit number is greater than a 3-digit number.
So, 614 < 1700
b. 5092 < 7320
Compare digits at the thousands place 5 < 7.
So, 5092 < 7320
c. 2184 < 2357
Compare digits at the thousands place 2 = 2. Since the digits are the same, compare the digits at the hundreds place.
The digits at the hundreds place, 1 < 3.
So, 2184 < 2357
d. 5720 > 5265
Compare digits at thousands place, 5 = 5. Since the digits are the same, compare the digits at the hundreds place.
The digits at the hundreds place, 7 > 2.
So, 5720 > 5265
e. 4126 < 4510
Compare digits at the thousands place, 4 = 4. Since the digits are the same, compare the digits at the hundreds place.
The digits at the hundreds place, 1 < 5.
So, 4126 < 4510
f. 5271 > 5261
Compare digits at thousands place, 5 = 5. Since the digits are the same, compare the digits at the hundreds place.
The digits at the hundreds place, 2 = 2. Since the digits are the same, compare the digits at the tens place.
The digits at tens place, 7 > 6.
So, 5271 > 5261
3. Ascending order
a. Compare the digits at the thousands place, 1 < 4 < 7. Since the digits in the thousands place of 7430 and 7935 are the same, compare the digits at the hundreds place 4 < 9.
So, 1765 < 4390 < 7430 < 7935 1765, 4390, 7430, 7935
b. A 3-digit number is less than a 4-digit number 773 is the smallest number
Compare the digits in the thousands place of 2860, 7880 and 9573, 2 < 7 < 9.
So, 773 < 2860 < 7880 < 9573 773, 2860, 7880, 9573
c. A 3-digit number is less than a 4-digit number.
392 is the smallest number
Compare the thousands digit of 3067, 4853 and 7943, 3 < 4 < 7.
So, 392 < 3067 < 4853 < 7943
392, 3067, 4853, 7943
d. A 3-digit number is less than a 4-digit number 157 is the smallest number.
Compare the digits at thousand place of numbers 6583, 8546 and 9404, 6 < 8 < 9.
So, 157 < 6583 < 8546 < 9404 157, 6583, 8546, 9404
Descending order
a. The digits at the thousands place of 7935 and 7430 are the same, compare the digits at the hundreds place: 9 > 4. 7935 > 7430
The digits in the thousands place of 4390 is greater than the digit at the thousands place of 1765.
4390 > 1765
So, 7935 > 7430 > 4390 > 1765
7935, 7430, 4390, 1765
b. Compare the digits in the thousands place of the given numbers—9573, 7880, 2860, 773
9 > 7 > 2
So, 9573 > 7880 > 2860 > 773 9573, 7880, 2860, 773
c. Compare the digits in the thousands place of the given numbers—7943, 4853, 3067 and 392
7 > 4 > 3
So, 7943 > 4853 > 3067 > 392 7943, 4853, 3067, 392
d. Compare the digits in the thousands place of the given numbers—9404, 8546, 6583, 157
9 > 8 > 6
9404 > 8546 > 6583 > 157 9404, 8546, 6583, 157
4. To form the smallest number, the digits from the thousands place to the ones place should be in ascending order.
Smallest:
a. 2 < 4 < 6 < 7, smallest number = 2467
b. 1 < 3 < 6 < 7, smallest number = 1367
c. 0 < 1 < 2 < 5, a 4-digit number cannot start with 0. Smallest number = 1025
d. 0 < 5 < 6 < 8, 4-digit number cannot start with 0. Smallest number = 5068
e. 0 < 2 < 8 < 9, a 4-digit number cannot start with 0. Smallest number = 2089
f. 0 < 1 < 5 <7, a 4-digit number cannot start with 0.
Smallest number = 1057
g. 2 < 5 < 7 < 8, smallest number = 2578
h. 2 < 4 < 8 < 9, smallest number = 2489
To form the greatest number, the digits from the thousands place to the ones place should be in descending order.
Greatest:
a. 7 < 6 > 4 > 2. Greatest number = 7642
b. 7 > 6 > 3 > 1. Greatest number = 7631
c. 5 > 2 > 1 > 0. Greatest number = 5210
d. 8 > 6 > 5 > 0. Greatest number = 8650
e. 9 > 8 > 2 > 0. Greatest number = 9820
f. 7 > 5 > 1 > 0. Greatest number = 7510
g. 8 > 7 > 5 > 2. Greatest number = 8752
h. 9 > 8 > 4 > 2. Greatest number = 9842
5. A 9999
B 1000
C 9876
D 1023
Smallest 4-digit number
Greatest 4-digit number
Smallest 4-digit number using different digits
Greatest 4-digit number using different digits
6. Length of river Nile = 6650 km
Length of river Amazon = 6575 km
The digit at the hundreds place of 6650 is greater than the digit at hundreds place of 6575. (6 > 5 )
So, the length of river Nile is greater than river Amazon.
7. The digits are 7, 3, 2 and 5.
To form the largest number, the digits from the thousands place to the ones place should be in descending order
7 > 5 > 3 > 2.
The largest number possible using the same digits is 7532.
Challenge
1. The largest number written by Anahita can be 9999. The largest number written by Hetal can be 9876. Since digits at the thousands place of 9999 and 9876 are the same, compare the digits at the hundreds place: 9 > 8. 9999 > 9876
So, the 4-digit number written by Anahita is the largest number.
Do It Yourself 1C
1. a. There are 38 students in my class. 38 can be rounded off to 40.
b. There are 73 trees in a park. 73 can be rounded off to 70.
c. 44 is in between 40 and 50 but is closer to 40.
d. 123 is in between 120 and 130 but is closer to 120
2. a. 32 is less than 35. So, 32 is rounded off to 30.
b. 67 is greater than 65. So, 67 is rounded off to 70.
c. 81 is less than 85. So, 81 is rounded off to 80.
d. 137 is greater than 135. So, 137 is rounded off to 140.
e. 256 is greater than 255. So, 256 is rounded off to 260.
f. 321 is less than 325. So, 321 is rounded off to 320.
g. 442 is less than 445. So, 442 is rounded off to 440.
h. 547 is greater than 545. So, 547 is rounded off to 550.
4. Rina and Sia served food to 632 people. 632 is less than 635. So, 632 can be rounded off to 630. Hence, Rina and Sia served about 630 people.
5. Number of trains in Delhi Metro = 268 trains
Number of stations = 256 stations
268 trains rounded off to the nearest tens = 270 trains
256 stations rounded off to the nearest tens = 260 stations
Challenge
1. Number of digits in the required number = 3
Options we have = 718, 752 and 648
718 is greater than 715. So,718 is rounded off to 720. 752 is less than 755. So, 752 is rounded off to 750. 648 is greater than 645. So, 648 is rounded off to 650. So, numbers which can be round down is 752. Number which has odd tens digit = 752 Hence, the required number is 752. Thus option b is correct.
Chapter Checkup
1. a. One thousand four hundred forty-two = 1442
b. Three thousand eight hundred fifty-seven = 3857
c. Four thousand two hundred eight = 4208
d. Five thousand three hundred nine = 5309
e. Six thousand forty-five = 6045
f. Five thousand twenty-eight = 5028
2. a. 2471 = Two thousand four hundred seventy-one
b. 4205 = Four thousand two hundred five
c. 5374 = Five thousand three hundred seventy-four
d. 7308 = Seven thousand three hundred eight
e. 7564 = Seven thousand five hundred sixty-four
f. 8421 = Eight thousand four hundred twenty-one
3. a. 1056, Place value = 50
b. 3814, Place value = 10
c. 5807, Place value = 800
d. 8379, Place value = 8000
e. 7291, Place value = 7000
f. 9092, Place value = 90
4. a. 2000 + 100 + 80 + 5 = 2185
b. 3000 + 400 + 70 + 1 = 3471
c. 8000 + 80 + 9 = 8089
d. 5000 + 700 + 20 + 5 = 5725
e. 4000 + 600 + 0 = 4600
f. 6000 + 0 + 70 + 0 = 6070
5. a. 1382 = 1000 + 300 + 80 + 2
b. 3641 = 3000 + 600 + 40 + 1
c. 5327 = 5000 + 300 + 20 + 7
d. 6484 = 6000 + 400 + 80 + 4
e. 7500 = 7000 + 500 + 00 + 0
f. 9032 = 9000 + 000 + 30 + 2
6. To form the smallest number, the digits of the number are arranged in ascending order from the thousands place to the ones place.
Smallest number:
a. 0 < 1 < 2 < 3, 4-digit number cannot start with 0. Smallest number = 1023
b. 0 < 5 < 6 < 8, 4-digit number cannot start with 0. Smallest number = 5068
c. 2 < 4 < 5 < 8. Smallest number = 2458
d. 0 < 1 < 4 < 7, 4-digit number cannot start with 0. Smallest number = 1047
e. 2 < 3 < 4 < 7. Smallest number = 2347
f. 0 < 3 < 6 < 8, 4-digit number cannot start with 0. Smallest number = 3068
To form the greatest number, the digits of the number are arranged in descending order from thousands place to ones place.
Greatest number:
a. 3 > 2 > 1 > 0, Greatest number = 3210
b. 8 > 6 > 5 > 0, Greatest number = 8650
c. 8 > 5 > 4 > 2, Greatest number = 8542
d. 7 > 4 > 1 > 0, Greatest number = 7410
e. 7 > 4 > 3 > 2, Greatest number = 7432
f. 8 > 6 > 3 > 0, Greatest number = 8630
7. a. 860
3184
Th H T O
b. 4072 Th H T
d. 4856
Th H T O
e. 9030
Th H T O
f. 7465
Th H T O
8. Ascending order
a. Compare the digits in the hundreds place of the 3-digit numbers 565 and 730, 5 < 7.
Next, compare the digits in the thousands place of the 4-digit numbers 2390 and 8935, 2 < 8.
So, 565 < 730 < 2390 < 8935 565, 730, 2390, 8935
b. Compare the digits at the hundreds place of the 3-digit numbers 773 and 830, 7 < 8.
Next compare the digits in the thousands place of the 4-digit numbers 1860 and 7573, 1 < 7.
So, 773 < 880 < 1860 < 7573 773, 880, 1860, 7573
c. A 3-digit number is less than a 4-digit number
Compare the digits in the thousands place of the numbers 5853, 6943 and 7081, 5 < 6 < 7
So, 792 < 5853 < 6943 < 7081 792, 5853, 6943, 7081
d. A 3-digit number is less than a 4-digit number.
Compare the digits in the thousands place of the numbers 5683, 7846, 8704, 5 < 7 < 8
So, 657 < 5683 < 7846 < 8704 657, 5683, 7846, 8704
e. Compare the digits in the thousands place of the numbers 2 < 4 < 8.
The digits in the thousands place and the hundreds place of 8734 and 8753 are the same. Compare the tens digit of the number, 3 < 5.
So, 2265 < 4867 < 8734 < 8753 2265, 4867, 8734, 8753
f. Compare the digits in the thousands place of the numbers 5436, 7354, 7428, 8754, 5 < 7 < 8.
The digits in the thousands place of numbers 7354 and 7428 are same, compare the hundreds place 3 < 4. So, 5436 < 7354 < 7428 < 8754 5436, 7354, 7428, 8754
Descending order
a. Compare the digits in the thousands place of numbers 8935, 2390, 8 > 2.
Compare the digits in the hundreds place of 730 and 565, 7 > 5.
So, 8935 > 2390 > 730 > 565 8935, 2390, 730, 565
b. Compare the digits at the thousands place of numbers 7573 and 1860, 7 > 1.
Compare the digits at the hundreds place of numbers 880 and 773, 8 > 7.
So, 7573 > 1860 > 880 > 773
7573, 1860, 880, 773
c. Compare the digits at the thousands place of the number 7081, 6943 and 5853, 7 > 6 > 5.
A 4-digit number is greater than a 3-digit number.
So, 7081 > 6943 > 5853 > 792 7081, 6943, 5853, 792
d. Compare the digits at thousands place of numbers 8704, 7846 and 5683, 8 > 7 > 5.
A 4-digit number is greater than a 3-digit number.
So, 8704 > 7846 > 5683 > 657 8704, 7846, 5683, 657
e. Compare the thousands digit of the numbers, 8 > 4 > 2. The digit at the thousands and hundreds place of the numbers 8753 and 8734 are the same.
Compare the digits at tens place 5 > 3.
So, 8753 > 8734 > 4867 > 2265
8753, 8734, 4867, 2265
f. Compare the digits at the thousands place of numbers, 8 > 7 > 5.
The digits at thousands place of the number 7428 and 7354 are the same, compare the digit at hundreds place 4 > 3.
So, 8754 > 7428 > 7354 > 5436
8754, 7428, 7354, 5436
9. a. 64 is less than 65. So, 64 is rounded off to 60.
b. 97 is greater than 95. So, 97 is rounded off to 100.
c. 393 is less than 395. So, 393 is rounded off to 390.
d. 421 is less than 425. So, 421 is rounded off to 420.
10. Number of types of hornbills in the world = 62
62 is less than 65. So, 62 is rounded off to 60.
Rounded-off number = 60
So, there are about 60 types of hornbills in the world.
11. Answer may vary. Sample answer:
Anna saved ₹5500 and Divya saved ₹4510. Who saved more money?
Challenge
1. a. Number of legs a spider has = 8 (thousands place)
b. Number of wheels in a car = 4 (hundreds place)
c. Number of wings a bird has = 2 (tens place)
d. Number of faces in a cube = 6 (ones place)
The number is: 8426
Number name: Eight thousand four hundred twenty-six Expanded form: 8000 + 400 + 20 + 6
2. 43 is smallest of all the given numbers. So, 43 will come on the top circle.
905 is the greatest among all the given numbers. So, 905 will come on bottom circle.
284 and 168 are greater than 43 and less than 905. So, they will come on the circles on the right and left side.
Case Study
1. Mount Everest—8848 m
K2—8611 m
Annapurna—8041 m
Mount Kailash—6638 m
Compare the digits at the thousands place of numbers, 8 > 6 and the digits in the thousands place of 8848, 8041 and 8611 is the same. So, compare the digits at the hundreds place 0 < 6 < 8.
So, Mount Everest is the highest peak. Thus, option c is the correct answer.
2. Mount Everest—8848 m
K2—8611 m
Annapurna—8041 m
Mount Kailash—6638 m
Kedarnath—3583 m
Compare the digits in thousands place of numbers 3583, 6638, 8041, 8611, 8848, 3 < 6 < 8.
The digit in the thousands place are the same in 8848, 8611, 8041. Compare the digits in hundreds place—0 < 6 < 8. So, 3583 < 6638 < 8041 < 8611 < 8848
Mountain peaks in ascending order is—Kedarnath, Mount Kailash, Annapurna, K2, Mount Everest
3. We see that Kedarnath has the least mountain peak. Kedarnath – 3583 m = 3000 m + 500 m + 80 m+ 3 m
In words: Three thousand five-hundred eighty-three
4. Answers may vary
Chapter
2 Let’s Warm-up
Do It Yourself 2A
1. a. 36 + 1 = 37
37 > 35
So, 36 + 1 > 35
b. 87 + 0 = 87
87 < 98
So, 87 + 0 < 98
c. 789 + 5 = 794
5 + 789 = 794
789 + 5 = 5 + 789
d. 6 + 4 = 10
4 +
4. Students can expand any one number.
1 7 → 10 + 7
9 → 50 + 9
9 ← 80 + 9 e. 5 7 → 50 + 7 2 2 → 22
9 ← 72 + 7
6 3 → 60 + 3
5 → 25 8 8 ← 85 + 3
5. There are 3 tens and 7 ones in 37.
Jump 3 tens from 41 which is 71. From 71 jump 7 ones to the right, which is 78.
6. Number of butterfly species = 48
Number of species added to the park = 30
Total species in Bannerghatta National Park = 48 + 30 = 78
4 8 → 40 + 8
3 0 → 30
7 8 ← 70 + 8
So, there are 78 species in Bannerghatta National Park.
Challenge
1. No, it is not solved correctly.
Smallest number, using the digits 3 and 4 = 34
Greatest number, using the digits 3 and 4 = 43
We should add 43 + 34 and not 43 + 43.
There are 3 tens and 4 ones in 34.
We should jump 3 tens below from 43, we will reach 73. We should jump 4 ones from 73, which is 77.
Do It Yourself 2B
1. a. H T O
4 5 6 + 2 3 2 6 8 8 b. H T O 7 4 1 + 2 5 6 9 9 7
c. H T O 1 4 7 + 5 4 1 6 8 8
8
2. a. True, the sum of 144 and 215 is 359.
b. False, the sum of 121 and 212 is 333.
c. False, the sum of 541 and 145 is 686.
d. True, the sum of 614 and 314 is 928.
3. H T O
3 4 7 + 3 2 1 6 6 8
4. a. H T O 1 1 6 1 6 + 1 8 4 8 0 0 b. H T O 1
c.
5.
c. Th H T O
3 2 1 4 + 6 1 4 5 9 3 5 9 d. Th H T O 7 1 5 1 + 2 1 2 6 9 2 7 7
6. a. To find 1234 more than 5145, add 1234 and 5145.
Th H T O
5 1 4 5
+ 1 2 3 4
6 3 7 9 1234 more than 5145 is 6379.
b. To find 2174 more than 1211, add 2174 and 1211.
Th H T O
1 2 1 1
+ 2 1 7 4
3 3 8 5 2174 more than 1211 is 3385.
7. Amount spent on the raincoat = ₹456
Amount spent on the umbrella = ₹235
Total amount spent by Jaspal = ₹456 + ₹235 = ₹691
8. 209 can be drawn as: 108 can be shown as:
2 hundreds + 1 hundreds = 3 hundreds + =
9 ones and 8 ones = 17 ones = 1 tens and 7 ones + = =
So the sum is 209 + 108 = 317
9. Number of oranges in the first carton = 1245
Number of oranges in the second carton = 2311
Number of oranges in the third carton = 1421
Total number of oranges = 1245 + 2311 + 1421 = 4977
Thus, the farmer packed 4977 oranges in total. Number of oranges as in the thousands place (4) are shown as:
Challenge
1. a. The two largest numbers will have the largest sum. Compare the hundreds digit of the numbers, 6 > 5 > 2.
So, 614 > 539 > 286 > 239
539 and 614 are the two largest numbers.
So, let us add 539 and 614.
539 and 614 will give a 4-digit sum.
539 + 614 = 1153
Th H T O 1
5 3 9 + 6 1 4 1 1 5 3
b. Add the digits at the ones place and check if the answer is 10.
9 + 6 = 15 ≠ 10
9 + 4 = 13 ≠ 10
9 + 9 = 18 ≠ 10
6 + 4 = 10
So, add 286 and 614
286 + 614 = 900 H T O 1 1
2 8 6 + 6 1 4
9 0 0
c. Add the digits at the ones place and check which two numbers have 5 at the ones place.
9 + 6 = 15
So, add 239 and 286 239 + 286 = 525
1 2 3 9 + 2 8 6 5 2 5
Do It Yourself 2C
1. a. 17 is greater than 15. So, 17 rounded off to the nearest 10 = 20
34 is less than 15. So, 34 rounded off to the nearest 10 = 30
Estimated sum = 20 + 30 = 50
b. 84 is less than 85. So, 84 rounded off to the nearest 10 = 80 17 is greater than 15. So, 17 rounded off to the nearest 10 = 20
Estimated sum = 80 + 20 = 100
c. 15 is equal to 15. So, 15 rounded off to the nearest 10 = 20
54 is less than 55. So, 54 rounded off to the nearest 10 = 50
Estimated sum = 20 + 50 = 70
d. 47 is greater than 45. So, 47 rounded off to the nearest 10 = 50
41 is less than 45. So, 41 rounded off to the nearest 10 = 40
Estimated sum = 50 + 40 = 90
2. a. 31 is less than 35. So, 31 rounded off to the nearest 10 = 30
36 is greater than 35. So, 36 rounded off to the nearest 10 = 40
Estimated sum = 30 + 40 = 70
Actual answer = 67
Thus, the estimated answer is close to the actual answer.
b. 58 is greater than 55. So, 58 rounded off to the nearest 10 = 60
23 is less than 25. So, 23 rounded off to the nearest 10 = 20
Estimated sum = 60 + 20 = 80
Actual answer = 81
Thus, the estimated answer is close to the actual answer.
c. 12 is less than 15. So, 12 rounded off to the nearest 10 = 10
17 is greater than 15. So, 17 rounded off to the nearest 10 = 20
Estimated sum = 10 + 20 = 30
Actual answer = 29
Thus, the estimated answer is close to the actual answer
d. 21 is less than 25. So, 21 rounded off to the nearest 10 = 20
47 is greater than 45. So, 47 rounded off to the nearest 10 = 50
Estimated sum = 20 + 50 = 70
Actual answer = 68
Thus, the estimated answer is close to the actual answer
3. Number of cookies made = 43
43 is less than 45. So, rounded-down number of cookies = 40
Number of puff pastries = 66
66 is greater than 65. So, rounded-up number of puff pastries = 70
Estimated number of items = 40 + 70 = 110
Thus, Ria made a total of 110 food items.
4. Number of star fishes found by Nisha = 78
78 is greater than 75. So, rounded-up number of fishes = 80
Number of star fishes found by Rohit = 52
52 is less than 55. So, rounded-down number of star fishes = 50
Total number star fishes found by Nisha and Rohit = 80 + 50 = 130
Thus, Nisha and Rohit found 130 star fishes in total.
5. a. 48 is greater than 45. So, 48 rounded off to the nearest 10 = 50
32 is less than 35. So, 32 rounded off to the nearest 10 = 30
Estimated sum = 50 + 30 = 80
The actual sum of the numbers = 80
Thus, the answer is the same in both cases.
b. 35 is equal to 35. So, 35 rounded off to the nearest 10 = 40
57 is greater than 55. So, 57 rounded off to the nearest 10 = 60
Estimated sum = 40 + 60 = 100
The actual sum of the numbers = 92
Rounding off the actual sum to the nearest 10 = 90
Thus, the answer is not the same in both cases.
c. 52 is greater than 55. So, 52 rounded off to the nearest 10 = 50
19 is greater than 15. So, 19 rounded off to the nearest 10 = 20
Estimated sum = 50 + 20 = 70
The actual sum of the numbers = 71
Rounding off the actual sum to the nearest 10 = 70
Thus, the answer is the same in both cases.
d. 11 is less than 15. So, 11 rounded off to the nearest 10 = 10
Estimated sum = 10 + 10 = 20
The actual sum of the numbers: 21
21 is less than 25. So, rounding down the actual sum to the nearest 10 = 20
Thus, the answer is the same in both cases.
Challenge
1. Score in round 1 = 35
35 is equal to 35. So, rounded-up score in round 1 = 40
Score in round = 48
48 is greater than 45. So, rounded up score in round 2 = 50
Sum of scores in round 1 + round 2 = 40 + 50 = 90
Total estimated score = 170
Rounded-off total in round 3 should be 80 to get 170 points. The score of round 3 should be between 75 and 84 to get 80 points.
Do It Yourself 2D
1. Number of toys sold in the month of January = 134
Number of toys sold in the month of February = 217
Total toys sold in January and February = 134 + 217 = 351
Thus, the total number of toys sold in both months are 351.
2. The cost of a bicycle = ₹4231
The cost of a music system = ₹4566
The total cost of both things = 4231 + 4566 = 8797
Thus, the total cost of both the bicycle and music system is ₹8797.
3. Number of seeds the first packet contains: 28
Number of seeds the second packet contains: 35
Number of seeds in total: 28 + 35 = 63
Thus, the total seeds are 63.
4. Number of students enrolled in Grade 2 = 218 students
Number of students enrolled in Grade 3 = 317 students
Number of students enrolled in Grade 4 = 165 students
Total number of students enrolled = 218 + 317 + 165 = 700 students
Thus, 700 students have enrolled altogether.
5. Length of Sankesula Barrage = 1300 m
Length of Nagarjuna Sagar Dam = 1300 + 250 = 1550 m
Thus, the length of Nagarjuna Sagar Dam is 1550 m.
6. a. Money spent on the hair dryer = ₹3015
Money spent on the quilt = ₹2150
The total amount of money spent on both things = ₹3015 + ₹2150 = ₹5165
Thus, ₹5165 was spent in total.
b. Money spent on a bottle of perfume = ₹900
Money spent on a bag = ₹220
Total money spent on both of the things = ₹900 + ₹220 = ₹1120
Thus, ₹1120 was spent in total.
c. Money spent by Mr Saxena if he bought all the 4 items = ₹5165 + ₹1120 = ₹6285
Thus, ₹6285 was spent in total.
7. Answer may vary. Sample answer:
Uma has collected 726 red roses and 492 yellow roses. How many roses has Uma collected in all?
Challenge
1. Number of beads with Nisha = 3 green + 4 red + 3 blue = 3 hundreds + 4 tens + 3 ones = 343
Number of beads with Ria = 5 green + 6 red + 2 blue = 5 hundreds + 6 tens + 2 blue = 562
Total number = 343 + 562
The beads will make the number 905.
Chapter Checkup
1. a. 45 + 1 = 46
Any number added to 1, the sum is the successor
b. 14 + 0 = 14
Any number added to 0, the sum is number itself.
c. 87 + 48 = 48 + 87
Number can be added in any order, sum will be the same.
d. 5 + 3 = 3 + 5
Number can be added in any order, sum will be the same.
e. 1 + 83 = 84
Any number added to 1, the sum is the successor.
f. 0 + 18 = 18
Any number added to 0, the sum is the number itself.
a. 84 + 8
84 is less than 85. So, 84 rounded off to the nearest 10 = 80
8 is greater than 5. So, 8 rounded off to the nearest 10 = 10
Estimated sum = 80 + 10 = 90
b. 34 + 17
34 is less than 35. So, 34 rounded off to the nearest 10 = 30
17 is greater than 15. So, 17 rounded off to the nearest 10 = 20
Estimated sum = 30 + 20 = 50
c. 25 + 52
25 is equal to 25. So, 25 rounded off to the next 10 = 30
52 is less than 55. So, 52 rounded off to the nearest 10 = 50
Estimated sum = 30 + 50 = 80
5. a. 56 + 11 = 67
67 is greater than 65. So, rounding off the result to the nearest 10 = 70
b. 23 + 49 = 72
72 is less than 75. So, rounding off the result to the nearest 10 = 70
c. 45 + 36 = 81
81 is less than 85. So, rounding off the result to the nearest 10 = 80
6.
7. a. 78 more than 361 = 361 + 78 = 439 b. 145 more than 456 = 456 + 145 = 601
c. 847 more than 254
Number of tazos collected by Ishan in 2 weeks = 37
Total number of tazos with Ishan = 65 + 37 = 102
carry 1 1 6 5 + 3 7
1 0 2
Thus, Ishan has 102 tazos.
11. Answer may vary. Sample answer:
Akil has made 1230 candles, and Anu has made 528 more candles than Akil. How many candles have they made in total?
Challenge
1. 100 + 70 + 130 = 300
130 + 50 + 120 = 300
100 + 80 + 120 = 300
H T O 1 1 1 2 5 4 + 8 4 7 1 1 0 1
e. 748 more than 369 = 369 + 748 = 1117
H T O 1 1 1 3 6 9 + 7 4 8 1 1 1 7
2 5
6 = 254 + 847 = 1101
f. 415 more than 871 = 871 + 415 = 1286
8. Number of mathematics books = 1025
Number of science books = 987
Number of Hindi books = 689
The total number of books in the library = 1025 + 987 + 689 = 2701
Thus, the total number of books in the library is 2701.
9. a. Boys in the Carnival = 1023
Girls in the Carnival = 1988
Total boys and girls in the Carnival = 1023 + 1988 = 3011
Thus, a total number of 3011 boys and girls went to the Carnival.
b. Men in the Carnival = 1547
Women in the Carnival = 2048
Total men and women in the Carnival = 1547 + 2048 = 3595
Thus, a total number of 3595 men and women went to the Carnival.
c. Boys in the Carnival = 1023
Girls in the Carnival = 1988
Men in the Carnival = 1547
Women in the Carnival = 2048
Total number of people in the Carnival = 1023 + 1988 + 1547 + 2048 = 6606
Thus, a total of 6606 people went to the carnival.
10. Number of tazos with Vishwa = 47
Number of tazos Ishan had 2 weeks earlier = 47 + 18 = 65
carry 1 4 7 + 1 8
6 5
2. Estimated sum of 2 numbers = 30
The first number = 23
23 is less than 25. So, 23 rounded off to nearest 10 is 20. The second rounded-off number = 30 − 20 = 10
The 1-digit numbers that can be rounded off to 10 are the digits which are equal to 5 or greater than 5. These are 5, 6, 7, 8 and 9.
Case Study
1. Number of leopards in Bihar = 32
32 is less than 35. So, 32 rounded off gives 30.
Number of leopards in Goa = 71
71 is less than 75. So, 71 rounded off gives 70.
So, the estimated number of leopards in Bihar and Goa = 30 + 70 = 100
Hence, option c is correct.
2. Number of leopards in Kerela = 472
Number of leopards in Andhra Pradesh = 343
Total leopards in Kerela and Andhra Pradesh = 472 + 343 = 815
Thus, there are 815 leopards in total.
3. Number of leopards in Chhattisgarh = 846
Total leopards in Kerela and Andhra Pradesh = 815
Since the digits in the hundreds place of 846 and 815 are the same, compare the digits at the tens place. 4 > 1, so 846 > 815.
The total leopards in Kerela and Andhra Pradesh are less than the number of leopards in Chhattisgarh.
4. Answers may vary.
Chapter 3
Let’s Warm-up
Do It Yourself 3A
1. a. True, a number subtracted from 0 is the number itself.
b. True, a number subtracted from itself is zero.
c. False, a number subtracted from 0 is the number itself.
d. True, 1 subtracted from a number is the predecessor.
e. False, a number subtracted from itself is zero.
f. False, a number subtracted from 0 is the number itself.
2. a. 21 − 13
Adding the jumps
7 + 1 = 8
21 − 13 = 8
b. 45 − 36
Adding the jumps
4 + 5 = 9
45 − 36 = 9
c. 56 − 27
Adding the jumps
3 + 10 + 10 + 6 = 29
56 − 27 = 29
3. a. 41 − 17
Breaking the smaller number into tens and ones:
Subtracting the tens from the bigger number,
41 − 10 = 31
Subtracting the ones from 31,
31 − 7 = 24
41 − 17 = 24
b. 63 − 26
Breaking the smaller number into tens and ones:
Subtracting the tens from the bigger number,
63 − 20 = 43
Subtracting the ones from 43, 43 − 6 = 37
63 − 26 = 37
c. 71 − 24
Breaking the smaller number into tens and ones:
Subtracting the tens from the bigger number,
71 − 20 = 51
Subtracting the ones from 51, 51 − 4 = 47
51 − 24 = 47
4. Number of species of fish = 43
Number of species of fish shifted = 15
Number of species of fish left = 43 − 15
15 20 30 40 43 +5 +10 +10 +3
There are two jumps of tens when 15 is subtracted from 43.
5. Number of roses Jaya had = 61
Number of roses Jaya gave her sister = 46
Number of roses left with Jaya = 61 − 46
+10
There is 1 jump of tens when 46 is subtracted from 61.
Jeny will have 15 roses left with her. 6. 46 56 66 69 +10 +10 +3
The total of jumps taken by Dan = 10 + 10 + 3
Dan is subtracting from 46 + 10 + 10 + 3 = 69
Dan is subtracting 46 from 69.
Challenge
1. Outer triangle:
58 − 29 = 29
75 − 29 = 46
75 − 58 = 17
Inner triangle: 29 − 17 = 12
9 14
4. Number of bottles Yukti collected = 469
Number of fewer bottles Priya collected than Yukti = 227
Number of bottles Priya collected = 469 − 227 = 242
Priya has collected 242 bottles.
5. a. Number of tickets sold by Joginder = 282
Number of tickets sold by Mohan = 178
Number of fewer tickets sold by Akhil than Joginder and Mohan = (282 + 178) − 159 carry 1 1 2 8 2 + 1 7 8 4 6 0
Number of tickets sold by Akhil = (282 + 178) − 159 = 460 − 159 = 301
5 10
4 6 0 1 5 9
3 0 1
Akhil has sold 301 tickets.
b. Number of tickets sold by Joginder = 282
Number of more tickets he needs to sell to reach 350 = 350 − 282 = 68 14
2 5 10
3 5 0 2 8 2 0 6 8
Joginder needs to sell 68 more ticket to reach 350.
Number of tickets sold by Mohan = 178
Number of more tickets he needs to sell to reach 350 = 350 − 178 = 172 14
2 4 10
3 5 0 1 7 8 1 7 2
Mohan needs to sell 172 more ticket to reach 350.
Number of tickets sold by Prasad = 331
Number of more tickets he needs to sell to reach 350 = 350 − 331 = 19
4 10
3 5 0
3 3 1
0 1 9
Prasad needs to sell 19 more tickets to reach 350.
6. Number of bones in deer = 327
Number of bones in cat = 235
Difference in number of bones = 327 − 235 = 92
To verify the answer, add the difference to 235 = 235 + 92 = 327 H T O 1 2 3 5 + 9 2 3 2 7
Challenge
1. To form the largest number, the digits 5, 8 and 2 are arranged in descending order from hundreds place to ones place. 8 > 5 > 2. So, the largest number using the digits 5, 8 and 2 = 852
To form the smallest number, the digits 5, 8 and 2 are arranged in ascending order from hundreds place to ones place. 2 < 5 < 8. So, the smallest number using the digits 5, 8 and 2 = 258
Difference between the numbers = 852 − 258 = 594 H T O 14
4
Thus, the difference between the numbers is 594.
Do It Yourself 3C
1. a. 3468 − 5 = 3463 b. 5296 − 40 = 5256
H T O
4 6
c. 6807 − 600 = 6207 d. 8547 − 7000 = 1547
Compare the digits at thousands place of the numbers 3331, 3011, 8100 and 8815, 3 < 8
Since the digits in the thousands place is the same in 3331, 3011, compare the digits at hundreds place of 3331 and 3011, 0 < 3
Since the digits in the thousands place is the same in 8100 and 8815, compare the digits at hundreds place of 8100 and 8815, 1 < 8 So, 3011 < 3331 < 8100 < 8815
The numbers in ascending order are: 3011, 3331, 8100, 8815
4. Number of government schools in Mizoram = 3872
Number of government schools in Nagaland = 2702
There are 1170 more schools in Mizoram than Nagaland.
Th H T O
3 8 7 2 – 2 7 0 2
1 1 7 0
5. Amount needed by Amit = ₹6987
Amount arranged by Amit = ₹5860
Amount needed by Amit = ₹6987 − ₹5860 = ₹1127
Th H T O
6 9 8 7 – 5 8 6 0 1 1 2 7
Challenge
1. THAR = 9869 DOWN = 3423
Th H T O
9 8 6 9 – 3 4 2 3
6 4 4 6
6 is equal to A, and 4 is equal to O. 6446 = AOOA
Thus, 6446 is equal to AOOA.
Do It Yourself 3D
1.
2. a. 43 – 31
Estimated difference:
58 – 36
3. Number of seashells Ajay collected = 42
Rounding off the number of seashells Ajay have = 40
Number of seashells he gave to Vijay = 23
Rounding off the number of seashells Vijay have = 20
Number of seashells Ajay has after giving to Vijay = 40 − 20 = 20
Rounding off to the nearest ten, Ajay now has about 20 seashells.
4. No, Arun had rounded off incorrectly.
43 is less than 45, so 43 will be rounded off to 40 and not 50. 19 is greater than 15, so 19 will be rounded off to 20.
Difference = 40 − 20 = 20
5. Total number of chocolates = 96
96 is greater than 95, so 96 can be rounded off to 100
Number of chocolates distributed by Navin = 17 17 is greater than 15, so 17 will be rounded off to 20.
Number of chocolates left = 68
68 is greater than 65, so 68 can be rounded off to 70.
Number of chocolates distributed by Darshana = Total chocolates − (Number of cholates distributed by Navin + Number of chocolates left) = 100 − (20 + 70) = 100 − 90 = 10
Thus, Darshana distributed about 10 chocolates.
Challenge
1. The smallest possible 2-digit number using any 2 digits from 5, 9, 8, 1 can be formed by arranging the smallest digits in the tens and ones places. 1 < 5 < 8 < 9.
Smallest 2-digit number = 15
Rounded-off number = 20
The greatest possible 2-digit number using any 2 digits from 5, 9, 8, 1 can be formed by arranging the largest digits in the tens and ones places. 9 > 8 > 5 > 1.
Greatest 2-digit number = 98
Rounded-off number = 100
Estimated sum of numbers = 20 + 100 = 120
Estimated difference of numbers = 100 − 20 = 80
Do It Yourself 3E
1. Number of stickers with Ravi = 478
Numbers of stickers with Shashi = 689
Shashi has more stickers.
Number of more stickers with Shashi = 689 − 478 = 211
Shashi has 211 more stickers than Ravi.
2. Runs scored by Team A = 435
Lesser runs scored by Team B = 146
Runs scored by Team B = 435 − 146 = 289
Team B scored 289 runs.
3. Amount with Amisha = ₹700
Amount spent by Amisha = ₹592
Amount left with Amisha = ₹108
4. Number of wheat bags in the warehouse = 5397
Number of wheat bags taken out = 3075
Number of wheat bags remained in warehouse = 5397 − 3075 = 2322
There are 2322 wheat bags remaining in the warehouse.
5. Number of shoes Nikhil bought in January = 5788
Number of shoes left on 1st February = 1475
Number of shoes Nikhil sold in January = 5788 − 1475 = 4313
Nikhil sold 4313 shoes in January
6. Number of stamps with Amit = 467
Number of stamps his father has given = 133
Total number of stamps = 467 + 133 = 600
Number of stamps Amit wants = 800
Number of more stamps Amit needs to collect = 800 − 600 = 200
Amit requires 200 more stamps.
7. Number of packages with Narendra = 442
Number of packages delivered by Narendra = 174
Remaining packages with Narendra = 442 − 174 = 268
Number of packages with David = 464
Number of packages delivered by David = 188
Remaining packages with Narendra = 464 − 188 = 276
Narendra is closer to finishing his deliveries.
8. Money Laila had = ₹5275
Money, she spent = ₹3142
Money left with Laila = ₹5275 − ₹3142 = ₹2133
Laila is left with ₹2133.
Th H T O
5 2 7 5 – 3 1 4 2
2 1 3 3
9. Answer may vary. Sample answer: Manju scored 794 points in a game and Raju scored 831 points. How many more points did Raju score more than Manju?
Challenge
1. Answers may vary. Sample answer:
To get a difference of 60, one rounded-off number can be 90 and the other rounded-off number can be 30.
Estimated difference = 90 − 30 = 60
To get 90 as rounded-off number, the actual number can be between 85 and 94.
To get 30 as rounded-off number, the actual number can be between 25 and 34.
Thus, the numbers are 93 and 32.
Chapter Checkup
1. a. 64 − 64 = 0
When the number is subtracted from itself the difference is 0.
b. 59 − 0 = 59
When 0 is subtracted from a number, the difference is number itself.
c. 93 − 1 = 92
When 1 is subtracted from a number, the difference is the predecessor.
d. 23 − 23 = 0
When the number is subtracted from itself the difference is 0.
e. 16 − 0 = 16
When 0 is subtracted from a number, the difference is number itself.
f. 75 − 1 = 74
When 1 is subtracted from a number, the difference is the predecessor.
2. a. 52 − 29
Adding the jumps
1 + 10 + 10 + 2 = 23
52 − 29 = 23
b. 61 − 46
Adding the jumps
4 + 10 + 1 = 15
61 − 46 = 15
c. 64 − 35
Adding the jumps
5 + 10 + 10 + 4 = 29
64 − 35 = 29
d. 92 − 67
Adding the jumps
3 + 10 + 10 + 2 = 25
92 − 67 = 25
e. 43 − 24
Adding the jumps
6 + 10 + 3 = 19
43 − 24 = 19
f. 71 − 42
Adding the jumps
8 + 10 + 10 + 1 = 29
71 − 42 = 29
3. a. 52 − 27
Breaking the smaller number into tens and ones:
Subtracting the tens from the bigger number,
52 − 20 = 32
Subtracting the ones from 32, 32 − 7 = 25
52 − 27 = 25
b. 84 − 55
Breaking the smaller number into tens and ones:
Subtracting the tens from the bigger number,
84 − 50 = 34
Subtracting the ones from 34, 34 − 5 = 29
84 − 55 = 29
4.
c. 76 − 29
Breaking the smaller number into tens and ones:
Subtracting the tens from the bigger number,
76 − 20 = 56
Subtracting the ones from 56, 56 − 9 = 47
76 − 29 = 47
d. 23 − 14
Breaking the smaller number into tens and ones:
Subtracting the tens from the bigger number, 23 − 10 = 13
Subtracting the ones from 13, 13 − 4 = 9
23 − 14 = 9
e. 68 − 49
Breaking the smaller number into tens and ones:
Subtracting the tens from the bigger number,
68 − 40 = 28
Subtracting the ones from 28, 28 − 9 = 19
68 − 49 = 19 f. 62 − 21
Breaking the smaller number into tens and ones:
Subtracting the tens from the bigger number,
62 − 20 = 42
Subtracting the ones from 42, 42 − 1 = 41
62 − 21 = 41
6. Number of pages kept for printing = 678
Number of pages have been printed = 259
Number of pages left for printing = 678 − 259 = 419
419 pages are left for printing.
7. Number of people who came to watch the match = 985
Number of people who left 1 hour into the match = 197
Remaining number of people = 985 − 197 = 788
Number of people who left before the half-time = 668
Remaining people who watched the whole match = 788 − 668 = 120
Thus, 120 people watched the whole match.
8. Potatoes bought by vendor from the market = 925 kg
Potatoes which are rotten = 123 kg
Remaining potatoes = 925 − 123 = 802 kg
Potatoes sold by vendor = 678 kg
Remaining potatoes with him = 802 − 678 = 124 kg
Thus, 124 kg potatoes are remaining.
9. First crewed landing on moon happened in 1969. Last crewed moon landing happened in 1972.
Difference = 1972 − 1969 = 3
The last crewed moon landing happened 3 years after the first crewed landing on moon happened.
10. Number of cardboard rolls collected = 915
Number of cardboard rolls used in the first exhibition = 268
Number of cardboard rolls used in the second exhibition = 380
Total Number of cardboard rolls used = 268 + 380 = 648
Number of cardboard rolls left = 915 − 648 = 267
Therefore, the artist is left with 267 cardboards.
11. Answer may vary. Sample answer:
There are 8567 books in a library. 1245 books were sent for binding. How many books were left in the library?
Challenge
1. Difference between 962 and 473 = 962 − 473 = 495
Difference between 609 and 473 = 609 − 473 = 136
Difference between 962 and 609 = 962 − 609 = 353
609 and 473 will have the least difference = 136 962 and 473 will have the highest difference = 495
Case Study
1. Option c
Number of post office in Goa = 258
Number of post office in Nagaland = 330
Difference = 330 − 258 = 72
We should jump 7 tens in the left of the line.
2. a. There are 82 fewer post offices in Nagaland than in Mizoram. True
Number of post offices in Nagaland = 330
Number of post offices in Mizoram = 412
Difference = 412 − 330 = 82
Thus, there are 82 fewer post offices in Nagaland.
H T O
3 11
4 1 2 –
3 3 0 8 2
b. There are 154 more post offices in Goa than in Mizoram. False
Number of post offices in Goa = 258
Number of post offices in Mizoram = 412
Difference in the number of offices = 412 − 258 = 154
H T O 10
3 0 12
4 1 2
– 2 5 8
1 5 4
Thus, there 154 less post offices in Goa than Mizoram.
3. Number of post offices in Haryana = 2689
Number of post offices in Jammu & Kashmir = 1684
Th H T O
2 6 8 9 – 1 6 8 4 1 0 0 5
There are 1005 more post offices in Haryana than in Jammu & Kashmir.
4. Number of post offices in Nagaland = 330
Number of post offices in Haryana = 2689
Th H T O
2 6 8 9 –
3 3 0
2 3 5 9
2359 is the difference in the number of post offices in Nagaland and Haryana.
5. Answers may vary.
Chapter 4
Let’s Warm-up
1. 3 + 3 + 3 + 3 = 4 × 3 = 12 2. 5 + 5 + 5 + 5 = 4 × 5 = 20
3. 10 + 10 + 10 = 3 × 10 = 30 4. 4 × 6 = 24 5. 6 × 8 = 48
Do It Yourself 4A
1. a. 3 + 3 + 3 + 3 + 3 = 5 × 3 b. 8 + 8 + 8 = 3 × 8
c. 2 + 2 + 2 + 2 = 4 × 2 d. 13 + 13 + 13 + 13 + 13 = 5 × 13
2. a. When you multiply any number by 1, you get the same number. True
b. When you multiply a number by 0, you always get 1. False
c. Order matters when multiplying numbers. False
3. 8 added 9 times is:
8 + 8 + 8 + 8 + 8 + 8 + 8 + 8 + 8 = 9 × 8
Option b is correct.
4. a. 9 × 3 = 3 × 9 b. 2 × 0 = 0 c. 1 × 7 = 7 d. 5 × 8 = 8 × 5
e. 47 × 94 = 47 × 94 f. 123 × 1 = 123
5. Number of elephants in each row = 15
Total number of rows = 2
Repeated addition = 15 + 15 = 30
Multiplication sentence = 2 × 15 = 30
6. 3 batches of 4 cookies will make: 3 × 4 = 12 cookies
4 cookies in 3 batches will make: 4 × 3 = 12 cookies
So, the total number of cookies will be the same whether Sophie multiplies 3 by 4 or 4 by 3. The order of multiplication doesn’t matter as the product always remains the same.
Challenge
1. Number of dots in each row = 5
Number of rows = 4
Total number of dots = 5 × 4 = 20
Number of dots removed = 4
New number of dots = 20 – 4 = 16
Multiplication sentence = 4 × 4 = 16
After removing the dots Rearrangement
Do It Yourself 4B
1. a. 1 week = 7 days
9 weeks = 9 × 7 = 63 days
9 weeks = 63 days b. 1 day = 24 hours
5 days = 5 × 24 = 120 hours
5 days = 120 hours
c. 1 hour = 60 minutes d. 1 week = 7 days So, 10 weeks = 10 × 7 days = 70 days
10 weeks = 70 days
2.
a 8 × 8 = 64
8 × 8 > 60
b. 9 × 10 = 90 and 100 × 1 = 100 9 × 10 < 100 × 1
c. 4 × 99 = 396 4 × 99 < 400 d. 6 × 7 = 42
3. a. 8 × 9 = 72
b. 10 × 10
Add 2 zeroes at the end and multiply 1 with 1: 10 × 10 = 100
c. 4 × 40
Add 1 zero at the end and multiply 4 with 4: 4 × 40 = 160
d. 80 × 3
Add one zero at the end and multiply 8 with 3: 80 × 3 = 240
e. 90 × 4
Add 1 zero at the end and multiply 9 with 4: 90 × 4 = 360
f. 700 × 10
Add 3 zeroes at the end and multiply 7 with 1: 700 × 10 = 7000
4. a. 8 × 8 = 64
b. Add one zero at the end and multiply 7 with 9 7 × 90 = 630
c. 560 7 = 80
7 × 80 = 560
d. 5400 6 = 900
6 × 900 = 5400
e. 400 4 = 100
100 × 4 = 400
f. 3600
6 = 600
600 × 6 = 3600
5. Number of friends = 9
Number of candies given to each friend = 6
Total candies distributed = 6 + 6 + 6 + 6 + 6 + 6 + 6 + 6 + 6
Or, 9 × 6 = 54
So, Raj distributed 54 candies among his friends.
6. 1 century = 100 runs
The player has scored 5 centuries. 5 centuries = 5 × 100
Add 2 zeroes at the end and multiply 5 and 1. 5 × 100 = 500
Thus, the player has scored 500 runs by centuries.
7. Answers may vary. Sample answer: The cost of a book is ₹45. What is the cost of 20 such books?
Challenge
1. Number of fours hit by Gautam Gambhir = 7
Total runs = 4 × 7 = 28
Number of sixes hit by Sachin Tendulkar = 3
Total runs = 6 × 3 = 18
Total runs scored by both through fours and sixes = 28 + 18 = 46
Chapter Checkup
1. a. 45 × 8 = 8 × 45 True, because the order does not matter when two numbers are multiplied by each other.
b. 4 × 6 = 24 True
c. 89745 × 0 = 89745 False, because when a number is multiplied by 0, the product is always 0.
d. 5 × 8 = 40 True
e. 9 × 8 = 72 True
f. 6 × 600 = 3600 True
2. a.
3. a. Pattern: Each number increases by 8. 8, 16, 24, 32, 40, 48, 56, 64
b. Pattern: Each number increases by 13. 13, 26, 39, 52, 65, 78, 91, 104
c. Pattern: Each number increases by 10. 30, 40, 50, 60, 70, 80, 90, 100
d. Pattern: Each number increases by 9. 18, 27, 36, 45, 54, 63, 72, 81
e. Pattern: Each number increases by 14. 14, 28, 42, 56, 70, 84, 98, 112
f. Pattern: Each number increases by 200. 200, 400, 600, 800, 1000, 1200, 1400, 1600
c. 44 × 100 = 4400 4400 < 4444
44 × 100 < 4444 d. 5 × 60 =
e. 48975 × 1 = 48975 48975 × 1 > 0
6. Total cookie boxes with Rajesh = 10 Cookies in each box = 7
Total cookies Rajesh has = Number of cookie boxes × Cookies in each box
= 10 × 7 = 70
Thus, Rajesh has a total of 70 cookies. Boxes are shown by rectangles and cookies are shown by circles.
7. Number of petals in a wild rose = 5
Number of wild roses = 6
Total number of petals = 5 × 6 = 30 petals
So, there are 30 petals in the bouquet.
8. Number of puppies in a litter = 8
Number of German Sheperd in the shelter house = 3
Total number of puppies = 8 × 3 = 24 puppies
9. Number of chocolates Vivan bought = 9
The price of each chocolate = ₹6
Total price of 9 chocolates = 9 × ₹6 = ₹54
Money Vivan paid to the shopkeeper = ₹100
Money he should get in return = ₹100 – ₹54 = ₹46
Challenge 1. 9 × 4 = 36 5 × 5 = 25
2. Number of layers in a fruit dessert = 9
Number of fruits in each layer = 8
Even numbers = 2, 4, 6 and 8. So, there are 4 even number layers.
Total number of grapes = 4 × 8 = 32
Odd numbers = 1, 3, 5, 7, and 9. So, there are 5 odd number layers.
Total number of blueberries = 5 × 8 = 40
Case Study
1. A wooden stacker toy has 6 rings. There are 2 such toys. The multiplication sentence for the number of rings is 6 × 2 = 12
2. Number of wheels for each wooden dog toy = 4
Total number of dog toys = 7
Total number of wheels for 7 dog toys = 4 × 7 = 28
Thus, option b is correct.
3. Cost of one wooden rattle = ₹90
Cost of 4 wooden rattle = 4 × ₹90
4 × 9 = 36
4 × ₹90 = ₹360
4. Number of plates = 2
Number of tumblers = 2
Number of spoons = 2
Number of pans = 2
Number of baskets = 2
Number of pots = 2
Total number of pieces = 2 + 2 + 2 + 2 + 2 + 2 = 6 × 2 = 12
5. Answers may vary.
Chapter 5
Warm-up
3. 100 20 3
3 × 3 × 100 = 300 3 × 20 = 60 3 × 3 = 9
300 + 60 + 9 = 369 2 tens are multiplied by 3.
4. 423 × 8 = 423 3384 × 8 = 3384 =
5. 333 × 3 = 999 3 0 9 0 9 0 9 9 3 9 9 9 0 9 9 3 3 0 The cabin travels 999 metres after 3 trips on the Rajgir ropeway.
Challenge
1. The error that Samir did are marked below:
Correct method to solve:
2 × 321 = 600 + 40 + 2 = 642
Do It Yourself 5B
1.
2. a. 3 4
4. The error that Daniel did are circled below.
6. 1 hour in Venus = 243 earth hours
7 hours in Venus = 243 × 7 = 1701 earth hours
Challenge
1. Number of sides in a square = 4
So, the number of walls required to build a pet house = 4
Number of bricks in each wall = 120
Number of bricks required for 4 walls = 120 × 4 = 480
Do It Yourself 5C
3. Amount of sugar required for 1 cotton candy = 14 g
Number of cotton candy = 21
Amount of sugar required for 21 cotton candies = 14 × 21 = 294 g 21 cotton candies need 294 g of sugar
5. Number of cloth pieces for each layer = 230
Number of layers in quilt = 5
Total
4. Number of rows = 23
Number of trees in each row = 5
Number of trees in the garden = 23 × 5
There are 115 trees in total.
Challenge
1. Greatest 2-digit number = 99
Smallest 2-digit number = 10
99 × 10 = 990
Do It Yourself 5D
1. a. The digit at the unit place is 5. Hence, 45 is rounded up to 50.
b. The digit at the unit place is more than 5. Hence, 36 is rounded up to 40
c. The digit at the unit place is more than 5. Hence, 78 is rounded up to 80
d. The digit at the unit place is less than 5. Hence, 91 is rounded down to 90.
e. The digit at the unit place is less than 5. Hence, 52 is rounded down to 50
f. The digit at the unit place is less than 5. Hence, 83 is rounded down to 80
g. The digit at the unit place is less than 5. Hence, 44 is rounded down to 40.
h. The digit at the unit place is more than 5. Hence, 27 is rounded up to 30
2. a. 44 × 5
The digit at the unit place is less than 5. Hence, rounding-off 44 to 40.
Add one zero at the end and multiply 4 with 5: 40 × 5 = 200
c. 26 × 4
The digit at the unit place is more than 5. Hence, rounding-off 26 to 30.
Add one zero at the end and multiply 3 with 4: 30 × 4 = 120
b. 32 × 6
The digit at the unit place is less than 5. Hence, rounding-off 32 to 30.
Add one zero at the end and multiply 3 with 6: 30 × 6 = 180
d. 81 × 2
The digit at the unit place is less than 5. Hence, rounding-off 81 to 80.
Add one zero at the end and multiply 8 with 2: 80 × 2 = 160
3. a. Rounding-off 66 to 70 Actual product
b. Estimated product Rounding-off 18 to 20 Actual
c. Estimated product Rounding off 45 to 50 Actual
d. Estimated product Rounding-off 33 to 30 Actual
5. Number of boxes = 45
Number of bangles in each box = 24
Estimated bangles packed: Rounding-off 45 to 50 and 24 to 20 Riya packed around 1000 bangles.
Challenge
1. Numbers rounded off to 50 are: 45, 46, 47, 48, 49, 50, 51, 52, 53, 54.
Products of the digit = 15 = 3 × 5 or 5 × 3
Hence, the number is 53.
Do It Yourself 5E
1. Number of boxes = 12
Number of erasers in each box = 13
Total number of erasers = 12 × 13
There are 156 erasers.
2. Cost of 1 notebook = ₹100
Number of notebooks = 12
Cost of 12 notebooks = 100 × ₹12 = ₹1200
The cost of 12 notebooks will be ₹1200
3. Number of apple trees in a row = 64
Number of rows = 7
Number of apples in the orchard = 64 × 7
There are 448 apple trees in all.
4. Number of scouts and guides leader in school = 12
Number of students under each leader = 26
Total number of students = 12 × 26 = 312
O 1 1 2 × 2 6
2 + 2 4 0 3 1 2
5. Number of packets = 54
Number of balloons in each packet = 45
Total number of balloons = 54 × 45
There will be 2430 balloons.
6. a. Price of 1 candle = ₹12
Price of 45 candles = 45 × ₹12
The price of 45 candles is ₹540.
4 5 × 1 2
0 + 4 5 0 5 4 0
c. Price of 1 bell = ₹45
Price of 45 bells = ₹45 × 45
Price of 45 bells is ₹2025.
b. Price of 1 star = ₹50
Price of 25 stars = ₹50 × 25
The price of 25 stars is ₹1250.
381 × 7 = 2667 3
7. Answer may vary. Sample answer:
There are 35 students in each section of grade 3. How many students are there in Grade 3, if there are 5 sections?
Challenge
1. Length of the swimming pool = 50 m
Deepak swims twice the same length = 2 × 50 m = 100 m Deepak practices swimming for 6 days.
Length covered in 6 days = 6 × 100 m = 600 m So, Deepak covered 600 m in 6 days.
Chapter Checkup
1. a. 62 × 0 = 0 T, because on multiplying a number by 0, the product is always 0.
b. 1 × 55 = 56 F, because on multiplying a number by 1, the product is always the number itself.
c. 1 × 91 = 92 F, because on multiplying a number by 1, the product is always the number itself.
d. 88 × 0 = 0 T, because on multiplying a number by 0, the product is always 0.
2. a. 10 2
4 × 4 × 10 = 40 4 × 2 = 8 Product: 40 + 8 = 48
b. 20 9
3 × 3 × 20 = 60 3 × 9 = 27 Product: 60 + 27 = 87
6. a. 12 will be 10 10 × 6 = 60
b. Rounding-off 34 to 30
30 × 4 = 120
c. Rounding-off 34 to 30
30 × 3 = 90
d. Rounding-off 44 to 40
40 × 2 = 80
7. Number of trips made by the bus = 16
Number of people seated in the bus = 76
Number of people travelled in the bus = 76 × 16
1216 people travelled in the bus.
8. Number of crates = 12
Number of apples in each crate = 45
Total number of apples = 12 × 45
There are 540 apples in 12 crates.
9. Number of chocolates = 6
Number of boxes = 15
Cost of each box = ₹9
Money needed to buy the chocolates = ₹9 × 15
Raj will need ₹135 to buy the chocolates.
10. Number of pages in the Constitution of India = 234
Number of books = 6
Total number of pages in 6 books = 234 × 6 = 1404 pages
11. Number of sheets = 56
Number of stickers in each sheet = 56
Total number of stickers = 56 × 56
There are 3136 stickers in total.
12. Number of buses = 39
Number of children who could sit in the bus = 25
Total number of children who went to picnic = 39 × 25
975 children went to the picnic.
13. Number of children = 36
Amount of money paid by each child = ₹50
Total amount paid = ₹50 × 36 ₹1800 was paid at the entrance.
14. Number of auditoriums = 4
Number of people who can sit in the auditorium = 425
Total number of people who can watch movie at one time = 425 × 4 = 1700
Total number of people who can watch the movie two times in the multiplex theatre = 2 × 1700 = 3400
15. Answer may vary. Sample answer:
The cost of 1 pencil box is ₹15. What is the cost of 25 pencil boxes?
Challenge
1. The sum of two numbers = 17
The numbers can be = 0 + 17; 1 + 16; 2 + 15; 3 + 14; 4 + 13; 5 + 12; 6 + 11; 7 + 10
The product of 9 × 8 = 72, 10 × 7 = 70, 11 × 6 = 66, 12 × 5 = 60, 13 × 4 = 52, 14 × 3 = 42, 15 × 2 = 30, 16 × 1= 16, 17 × 0 = 0
12 × 5 = 60
So, the numbers are 12 and 5.
2. 22 × 3 = 66
66 × 4 = 264
264 + 12 = 276
22 × 3 × 4 + 12 = 276
Case Study
1. ₹60 × 2 = ₹120
Hence, option d is correct.
2. ₹80 × 3 = ₹240 T O 8 0 × 3 2 4 0
3. Cost of toll at Nashri = ₹165
Number of cars = 7
Total cost = ₹165 × 7 = ₹1155 H T O 4 3 1 6 5 × 7 1 1 5 5
4. Cost of toll at Manavasi = ₹60
Cost of toll at Debra = ₹80
Cost of toll for 10 cars at Manavasi = ₹60 × 10 = ₹600
Cost of toll for 10 cars at Debra = ₹80 × 10 = ₹800
Total cost = ₹800 + ₹600 = ₹1400
5. Answers may vary
Chapter 6
Let’s Warm-up
Number of marbles = 6
1. The marbles can be distributed equally among 6 friends. True
Since, 6 ÷ 6 = 1
2. The marbles can be distributed equally among 2 friends. True
Since, 6 ÷ 2 = 3
3. The marbles can be distributed equally among 4 friends. False
Since, 6 is not divisible by 4. 4. The marbles can be distributed equally among 3 friends. True Since, 6 ÷ 3 = 2
Do It Yourself 6A
1. a. Number of cups = 8
Number of people = 4
Number of cups shared equally among 4 people = 8 ÷ 4 = 2 cups
b. Number of buttons = 21
Number of people = 7
Number of buttons shared equally among 7 people = 21 ÷ 7 = 3 buttons
c. Number of crayons = 18
Number of people = 9
Number of crayons shared equally among 9 people = 18 ÷ 9 = 2
2. There are 21 balloons.
Total number of colours = 3
Number of balloons of each colour = 21 ÷ 3 = 7
7 balloons of each colour:
Total number of apples = 18
Number of baskets = 3
Number of apples in each basket = 18 ÷ 3 = 6
4. a. Subtract 1 from 9 until we get zero. Count how many times 1 has been subtracted. We subtracted 1 for 9 times. So, there are nine
9.
b. Subtract 11 from 22 until we get zero. Count how many times 11 has been subtracted. We subtracted 11 for 2 times. So, there are two 11’s in 22.
2 2 – 1 1 1 1 – 1 1 0 1 2
c. Subtract 9 from 27 until we get zero. Count how many times 9 has been subtracted. We subtracted 9 for 3 times. So, there are three 9’s in 27.
5. Total number of rotis made by Karthik = 15
Number of people in the house = 5
Number of rotis each person gets = 15 ÷ 5
Thus, each member will get 3 rotis.
6. Total number of matchsticks = 36
Number of matchsticks used every day = 3
Subtract 3 from 36 until we get zero. It will take 12 days to finish all the matchsticks. 3
Challenge
1. 63 7 9 9 = 10
We try division because 10 is a small number, 63 ÷ 7 = 9 9 ÷ 9 = 1
1 + 9 = 10
Hence, the correct mathematical symbol to make the statement correct is: 63 ÷ 7 ÷ 9 + 9 = 10
Do It Yourself 6B
1. a. When we divide any number by 1, we get the same number back. Thus, 25 ÷ 1 = 25.
b. We cannot divide any number by 0. There is no answer. Thus, 12 ÷ 0 = No answer.
c. When we divide 0 by any number, the answer is always 0. Thus, 0 ÷ 5 = 0.
d. When we divide any number by itself, the answer is always 1. Thus, 9 ÷ 9 = 1.
e. When we divide 0 by any number, the answer is always 0. Thus, 0 ÷ 3 = 0.
d. Subtract 8 from 32 until we get zero. Count how many times 8 has been subtracted. We subtracted 8 for 4 times. So, there are four 8’s in 32.
f. We cannot divide any number by 0. There is no answer. Thus, 15 ÷ 0 = No answer
2. a. 6 × 10 = 60 Therefore, 60 ÷ 6 = 10
b. 4 × 9 = 36 Therefore, 36 ÷ 4 = 9
c. 7 × 8 = 56 Therefore, 56 ÷ 7 = 8
d. 2 × 14 = 28 Therefore, 28 ÷ 2 = 14
e. 3 × 9 = 27 Therefore, 27 ÷ 3 = 9
f. 4 × 8 = 32 Therefore, 32 ÷ 4 = 8
3. a. Division facts of 7 × 4 = 28 are: 28 ÷ 7 = 4 and 28 ÷ 4 = 7
b. Division facts of 5 × 9 = 45 are: 45 ÷ 5 = 9 and 45 ÷ 9 = 5
c. Division facts of 3 × 6 = 18 are: 18 ÷ 3 = 6 and 18 ÷ 6 = 3
d. Division facts of 8 × 2 = 16 are: 16 ÷ 8 = 2 and 16 ÷ 2 = 8
e. Division facts of 10 × 3 = 30 are: 30 ÷ 10 = 3 and 30 ÷ 3 = 10
f. Division facts of 6 × 7 = 42 are: 42 ÷ 6 = 7 and 42 ÷ 7 = 6
4. Dividend Divisor Quotient
a. 20 ÷ 2 = 10
b. 42 ÷ 6 = 7
c. 30 ÷ 6 = 5
d. 63 ÷ 9 = 7
5. Total cream rolls at the party = 18
Cream rolls each child gets = 1
Remember, the property of division: When you divide any number by 1, the answer is always a number itself.
Number of children in the party = 18 ÷ 1 = 18
There are 18 children in the party.
6. Number of notebooks with the teacher = 45
Number of students among which the notebooks are to be distributed = 9
Number of notebooks each student will get = 5
So, the multiplication fact for this is: 9 × 5 = 45
7. Number of trash pieces collected in an hour = 36
Number of bags they wanted to keep the trash into = 4
Chapter Checkup
1. a. Number of things = 15
Number of people = 3
Number of things shared equally among 3 people = 15 ÷ 3 = 5 things
b. Number of dice = 24
Number of people = 8
Number of dice shared equally among 8 people = 24 ÷ 8 = 3 dice
c. Number of coins = 12
Number of people = 6
Number of coins shared equally among 6 people = 12 ÷ 6 = 2 coins
d. Number of balls = 14
Number of people = 2
Number of balls shared equally among 2 people = 14 ÷ 2 = 7 balls
2. a. We divide 3 eight times from 24 until we get zero. Thus, 24 ÷ 3 = 8
b. We divide 6 six times from 36 until we get zero. Thus, 36 ÷ 6 = 6
Therefore, 36 ÷ 4 = 9
Thus, the group will keep 9 pieces of trash in each bag.
8. Answer will vary. Sample answer: Rahul bought 55 roses to put in vases in a party hall. If he put 5 roses in each vase, how many vases did he use?
Multiplication fact: 11 × 5 = 55
c. We divide 9 five times from 45 until we get zero. Thus, 45 ÷ 9 = 5
d. We divide 8 nine times from 72 until we get zero. Thus, 72 ÷ 8 = 9
e. We divide 7 eight times from 56 until we get zero. Thus, 56 ÷ 7 = 8
f. We divide 9 seven times from 63 until we get zero. Thus, 63 ÷ 9 = 7
6. Answers may vary. Sample answers:
a. Example 1: 25 ÷ 1= 25; Example 2: 43 ÷ 1 = 43
b. Example 1: 15 ÷ 15 = 1; Example 2: 32 ÷ 32 = 1
c. Example 1: 0 ÷ 17 = 0; Example 2: 0 ÷ 23 = 0
d. Example 1: 20 ÷ 0 = No answer; Example 2: 14 ÷ 0 = No answer
7. Number of toy cars = 20
Number of children = 20
Number of toy cars each child will receive = 20 ÷ 20
Remember, the property of division: When you divide any number by itself, the answer is always 1.
Thus, 20 ÷ 20 = 1
So, each child will get 1 car.
8. Total number of cupcakes = 32
Number of children = 4
Number of cupcakes each child will get = 32 ÷ 4
g. We divide 9 six times from 54 until we get zero. Thus, 54 ÷ 9 = 6
h. We divide 8 ten times from 80 until we get zero. Thus, 80 ÷ 8 = 10
3. a. Multiplication fact for 36 ÷ 3 = 12 is 12 × 3 = 36
b. Multiplication fact for 88 ÷ 4 = 22 is 22 × 4 = 88
c. Multiplication fact for 96 ÷ 8 = 12 is 12 × 8 = 96
d. Multiplication fact for 40 ÷ 5 = 8 is 8 × 5 = 40
e. Multiplication fact for 25 ÷ 5 = 5 is 5 × 5 = 25
f. Multiplication fact for 60 ÷ 6 = 10 is 10 × 6 = 60
g. Multiplication fact for 48 ÷ 6 = 8 is 8 × 6 = 48
h. Multiplication fact for 36 ÷ 9 = 4 is 4 × 9 = 36
4. a. Division facts of 9 × 5 = 45 are: 45 ÷ 9 = 5 and 45 ÷ 5 = 9
b. Division facts of 4 × 8 = 32 are: 32 ÷ 4 = 8 and 32 ÷ 8 = 4
c. Division facts of 5 × 3 = 15 are: 15 ÷ 5 = 3 and 15 ÷ 3 = 5
d. Division facts of 7 × 2 = 14 are: 14 ÷ 7 = 2 and 14 ÷ 2 = 7
e. Division facts of 4 × 6 = 24 are: 24 ÷ 4 = 6 and 24 ÷ 6 = 4
f. Division facts of 9 × 8 = 72 are: 72 ÷ 9 = 8 and 72 ÷ 8 = 9
g. Division facts of 2 × 10 = 20 are: 20 ÷ 2 = 10 and 20 ÷ 10 = 2
h. Division facts of 3 × 7 = 21 are: 21 ÷ 3 = 7 and 21 ÷ 7 = 3
5. a. 9 × 3 = 27. Therefore, 27 ÷ 9 = 3
b. 5 × 9 = 45. Therefore, 45 ÷ 5 = 9
c. 7 × 9 = 63. Therefore, 63 ÷ 7 = 9
d. 5 × 7 = 35. Therefore, 35 ÷ 5 = 7
e. 6 × 7 = 42. Therefore, 42 ÷ 6 = 7
f. 9 × 6 = 54. Therefore, 54 ÷ 9 = 6
g. 3 × 9 = 27. Therefore, 27 ÷ 3 = 9
h. 8 × 10 = 80. Therefore, 80 ÷ 8 = 10
Therefore, 32 ÷ 4 = 8
Thus, each child will get 8 cupcakes.
9. Number of people who visited Taj Mahal = 36
Number of people in a group = 6
Number of groups = 36 ÷ 6
Let us divide by repeated subtraction.
Subtract 6 from 36 until we get zero.
Count the number of times 6 has been subtracted.
We subtracted 6 six times.
Thus, there will be 6 groups of 6 people.
Challenge
1. By using any two numbers from the box the division sentence on the caterpillar is:
2. Answers may vary Sample answer:
24 ÷ 6 = 4
2 ÷ 2 = 1
12 ÷ 3 = 4
24 ÷ 2 = 12
6 ÷ 2 = 3
4 ÷ 1 = 4
Case Study
1. Total number of fish = 27
Number of tanks = 3
Number of fish in each tank = 27 ÷ 3
Let us divide by repeated subtraction.
Subtract 3 from 27 until we get zero.
Count the number of times 3 has been subtracted.
We subtracted 3 twelve times. Hence, the number of fish in each tank = 12
Hence, option c is correct.
4. Total number of fish = 18
Number of tanks = 3
Number of fish in each tank = 18 ÷ 3
Let us divide by repeated subtraction.
Subtract 3 from 18 until we get zero.
Count the number of times 3 has been subtracted.
We subtracted 3 six times. Hence, the number of fish in each tank = 6
Hence, True.
5. Answer may vary
Chapter 7
Let’s Warm-up 1. 16 ÷ 4 15
3 × 5
Do It Yourself 7A
We subtracted 3 nine times.
Hence, the number of fish in each tank = 9
Hence, option d is correct.
2. The division sentence for the number of fish in each tank is 27 ÷ 3 = 9
3. Total number of fish = 36
Number of tanks = 3
Number of fish in each tank = 36 ÷ 3
Let us divide by repeated subtraction.
Subtract 3 from 36 until we get zero.
Count the number of times 3 has been subtracted
c. 235 ÷ 4
5 8
4 2 3 5 – 2 0 3 5 – 3 2 3
Quotient = 58
Remainder = 3 d. 412 ÷ 5 8 2 5 4 1 2 – 4 0 1 2 – 1 0 2
Quotient = 82
Remainder = 2
3. (Quotient × Divisor) + Remainder = Dividend
a. 41 ÷ 2
2 0
2 4 1 – 4 0 1
(Q × D) + R = (20 × 2) + 1 = 40 + 1 = 41 = Dividend b. 132 ÷ 3 4 4 3 1 3 2 – 1 2 1 2 – 1 2 0 (Q × D) + R = (44 × 3) + 0 = 132 = Dividend
c. 324 ÷ 5 6 4 5 3 2 4 – 3 0 0 2 4 – 2 0 4
(Q × D) + R = (64 × 5) + 4 = 324 = Dividend d. 2562 ÷ 9 2 8 4 9
(Q × D) + R = (284 × 9) + 6 = 2562 = Dividend
4. a. (7 × 5) + 3 44
b. (12 × 4) + 1 41
c. (9 × 6) + 5 38
d. (5 × 8) + 4 49
e. (20 × 2) + 1 59
5. Total number of puppies in a shelter = 57
Number of puppies each dog house can have = 9
Number of puppies left without a doghouse = 57 ÷ 9 6 9 5 7 – 5 4 3
There are 3 puppies without a doghouse.
6. Number of flower seeds = 3548
Number of rows = 6
Number of seeds left after planting = 3548 ÷ 6 5 9 1
6 3 5 4 8 – 3 0 5 4 – 5 4 0 8 – 6 2
So, 2 seeds are left.
7. Number of cups = 74
Number of cups in each tray = 8
Number of trays needed = 74 ÷ 8 9 8 7 4 – 7 2 2
9 trays will hold 72 cups.
There are 2 extra cups, we would need an extra tray to hold them.
So, the total number of trays required: 9 + 1 = 10 trays
8. Number of storybooks = 513
Number of storybooks each classroom gets = 9
Number of classrooms = 513 ÷ 9
9 5
5 7
So, 57 classrooms will receive the storybooks.
9. Cost of 3 shirts of Brand A = ₹360
Cost of 5 shirts of Brand B = ₹475
Cost of 2 shirts of Brand C = ₹128
a. Cost of 1 shirt of Brand A = 360 ÷ 3 1 2 0 3 3 6 0 – 3 0 6 – 6 0 0
b. Cost of 1 shirt of Brand B = 475 ÷ 5
So, brand C is cheaper.
Challenge
1. The number divided by 7 gives 560.
Therefore, number ÷ 7 = 560 or number 560 7 =
To find the number, multiply 7 on both sides of equation number 75607 7 ×=×
number = 3920
Now, divide 3920 by 56 = 3920 ÷ 56
Hence, by dividing 3920 by 56 we get 70.
Chapter Checkup
1.
2.
59
3. (Quotient × Divisor) + Remainder = Dividend
a. 91 ÷ 4 2 2 4 9 1 – 8 1 1 – 8 3 (Q × D) + R = (22 × 4) + 3 = 91 = Dividend b. 125 ÷ 6 2 0 6 1 2 5 – 1 2 0 5 (Q × D) + R = (20 × 6) + 5 = 125 = Dividend
c. 645 ÷ 8 8 0 8 6 4 5 – 6 4 0 5
(Q × D) + R = (80 × 8) + 5 = 645 = Dividend
d. 1842 ÷ 6 3 0 7 6 1 8 4 2 – 1 8 0 4 2 – 4 2 0 (Q × D) + R = (307 × 6) + 0 = 1842 = Dividend
4. (Quotient × Divisor) + Remainder = Dividend
a. (10 × 4) + = 43 1 0 4 4 3 – 4 3 (10 × 4) + 3 = 43 b. ( × 2) + 1 = 49 2 4 2 4 9 – 4 9 – 8
d. (7 × 9) + = 64 7 9 6 4 – 6 3 1 (7 × 9) + 1 = 64
+
× 5) + 4 = 214
× 3) + 1 = 352
5. Number of tickets to be sold = 5245
Number of tickets in each booklet = 5
Number of booklets need to be prepared = 5245 ÷ 5 1 0 4 9 5 5 2 4 5 – 5 0 2 4 – 2 0 4 5 – 4 5 0
So, 1049 booklets need to be prepared.
6. Number of firefighters = 720
Number of groups = 3
Number of firefighters in each group = 720 ÷ 3 2 4 0 3 7 2 0 – 6 1 2 – 1 2 0 0 – 0 0
So, 240 firefighters will be there in a group.
7. Number of packets of pulses = 156
Number of packets given to each family = 10
Number of families who received the packets = 156 ÷ 10
So, 15 families received the packets.
Challenge
1. To find the number that needs to be added to 156 so that it can be divided by 7 without a remainder, we find the remainder when 156 is divided by 7.
2 2 7 1 5 6
Since the remainder is 2, we need to add enough to make the total divisible by 7. The next multiple of 7 after 154 is 161. Difference between 161 and 156 = 161 − 156 = 5 Therefore, the number that needs to be added to 156, so that it can be divided by 7 without a remainder is 5.
2. 88 cm Total height 256 cm
Total length 600 cm Number of steps = 16
a. Total height of the staircase = 256 cm
Height of each step = Total height ÷ Number of steps = 256 ÷ 16 = 16 cm
b. Total length of the staircase = 600 cm
Length of the staircase = 600 − 88 = 512 cm
Length of each step = Length of the staircase ÷ Number of steps
512 ÷ 16 = 32 cm
Case Study
1. Total weight of the stone = 56 ton Number of workers = 8
Weight each worker has to move = 56 ÷ 8 = 7 ton
Thus, option c is correct.
2. Total weight of the stone = 56 ton Number of workers = 4
Weight
So, twice as heavy would each worker ’s load be compared to having 8 workers.
Hence, option a is correct.
3. Dividing the weight of the stone by the number of workers makes the stone lighter. False
4. The fewer workers they have, the less each worker needs to carry. False
5. Answer may vary. Sample answer: Everyone needs to know exactly when to push or pull the levers together to move the block safely and avoid accidents.
Chapter 8
Let’s Warm-up
1. Objects having similar shapes.
3. Square = 2
Rectangle = 2
Triangle = 1
Circle = 6
4. a. A triangle has 3 curved sides. False
b. The opposite sides of a rectangle are equal in length. True
c. An oval has 0 sides and 0 corners. True
d. The 4 sides of a square are straight sides. True
5. Figures may vary. Sample figure:
Challenge
1. The given figure is made up of 6 squares.
Do It Yourself 8B
1. a. Figure a does not show symmetry along the dotted line.
b. Figure b shows symmetry along the dotted line.
c. Figure c does not show symmetry along the dotted line.
d. Figure d shows symmetry along the dotted line.
5. a. Go 4 steps up from the house and then 1 step to left then you will reach the park
b. Go 2 steps up and 2 steps right from the school and you will reach the hospital
c. Answers may vary. Sample answer:
A way to go from the park to the fire station without crossing the hospital, go 5 steps to the right then go 1 step up.
6. Answers may vary. Sample answer:
Challenge
1. These are called lines of symmetry. There are 4 lines of symmetry in the given rangoli.
Do It Yourself
2. a. 6 plane rectangular faces Cube
b. Only 1 curved face Cone
c. 1 plane and 1 curved face Cylinder
d. 6 plane square faces Cuboid
e. 2 plane faces and 1 curved face Sphere
3. Number of clay balls used = 8
Number of toothpicks used = 12
The clay balls will act as corners and the toothpicks will act as edges of the solid shape.
The length of all the toothpicks is equal. So, all the sides of the solid shape are the same.
The solid shape formed is a cube.
4. Answers may vary. Sample answer: A box, book or eraser when traced will give a rectangle.
2. a. b. c. d.
3. a. b. c.
4.
8C
1. a. Cube b. Cylinder
c. Sphere d. Cone
Challenge
1. 5 cubes when placed one over the another forms a cuboid.
When we trace the solid figure, we get a rectangle and a square.
Do It Yourself 8D
1. a. View B is the side view of the doughnut. View B
b. View B is the side view of the wooden box. View B
2. Images may vary a. , b. , c. ,
3. Drawings may vary a. b.
4. Drawings may vary. Sample drawings:
, The front view and the top view of the book are shown. We get a rectangle in each case.
The net of a book looks like as shown:
Challenge
1. A cuboid has a net where all its faces are rectangular in shape. Left Front Top Base Right Back
Do It Yourself 8E
1. a. The repeating unit is red hat, blue hat, brown hat.
b. The repeating unit is banana, apple, orange
c. The repeating unit is smiling face, neutral face, sad face
d. The repeating unit is red rocket, yellow rocket, blue rocket and again blue rocket
2. a. The pattern is pink balloon, yellow balloon, blue balloon.
b. The pattern is blue fish, yellow fish, red fish.
3. a. The pattern is one circle is adding each time.
b. The pattern is smiley are rotated anticlockwise and brown smiley, blue smiley, purple smiley, yellow smiley.
c. The pattern is figure is rotating clockwise.
d. The pattern is 1 outer circle is added each time.
e. Pattern: Each number increases by 4. 28, 32, 36, 40, 44, 48, 52
f. Pattern: Each number decreases by 10. 95, 85, 75, 65, 55, 45, 35
4. Option a, b and c show the tiling pattern. Option d does not show the tiling pattern since it has gaps between the circles. Thus, option d is correct.
5. a. JTJHJE JCJAJR JIJS JRJEJD
Here, letter ‘J’ is repeated before each alphabet
The secret message is ‘THE CAR IS RED’.
b. 1I 2L3I4K5E 6D7O8S9A
Here digits 1, 2, 3, 4, 5, 6, 7, 8, 9 appear before every alphabet.
The secret message is ‘I LIKE DOSA’.
6. Figures may vary. Sample figure:
Challenge 1.
Answer may vary. Sample answer: If the name is RAJ. It will be written as:
Chapter Checkup
1. a. The given shape as Square = 1
Rectangle = 7
Triangle = 2
Circle = 5
b. Drawing may vary Sample drawing:
Challenge
1. She can do it in 12 different ways. She will get only a cuboid.
2. 4 triangles can be made but 8 triangles can be seen.
7. a. Pattern: Each number increases by 4. 12, 16, 20, 24, 28, 32, 36, 40
b. Pattern: Each number increases by 8. 48, 56, 64, 72, 80, 88, 96
c. Pattern: Each number increases by 5. 32, 37, 42, 47, 52, 57, 62
d. Pattern: Each number increases by 3. 29, 32, 35, 38, 41, 44, 47
8. a. b.
Case Study
1. The ‘+’ sign shows the hospital. 2.
3. The (H) sign shows the hotel. Thus, option b is correct. 4. Step out on MG Road, turn to the right and walk straight. The house is on the left.
5. The top view of the parking area is given in the map.
Chapter 9
Let’s Warm-up
1. The book is 7 forearms long. False
Do It Yourself 9A
2. The watermelon is heavier than the pen True
3. The capacity of each glass is less than that of the jug True
1. a. The distance between two cities: Kilometres b. A pipe: Metres
2. a. b. c. d.
3. a. Cone b. Cube c. Cylinder d. Cuboid
9. Side: Rectangle Top: Circle
10. a. Colouring may vary
c. A phone: Centimetres
d. The length of hands of a person: Centimetres
2. a. The scissors start at 0 cm and ends at 8 cm. So, the length of the scissors is 8 cm.
b. The pen starts at 0 cm and ends at 11 cm. So, the length of the pen is 11 cm.
c. The nail starts at 0 cm and ends at 10 cm. So, the length of the nail is 10 cm.
d. The straw starts at 0 cm and ends at 15 cm. So, the length of the straw is 15 cm.
3. 1 m = 100 cm
a. 6 m = 6 × 100 cm = 600 cm
b. 8 m = 8 × 100 cm = 800 cm
c. 9 m 9 cm = 9 × 100 + 9 = 900 + 9 = 909 cm
d. 4 m 15 cm = 4 × 100 + 15 = 400 + 15 = 415 cm
e. 7 m 26 cm = 7 × 100 + 26 = 700 + 26 = 726 cm
f. 2 m 52 cm = 2 × 100 + 52 = 200 + 52 = 252 cm
4. 1 cm = 1 ÷ 100 m
a. 700 cm = 700 ÷ 100 = 7 m
b. 600 cm = 600 ÷ 100 = 6 m
c. 400 cm = 400 ÷ 100 = 4 m
d. 800 cm = 800 ÷ 100 = 8 m
e. 500 cm = 500 ÷ 100 = 5 m
f. 900 cm = 900 ÷ 100 = 9 m
5. Height of the building on which the tower is installed = 22 m
Height of the tower = 14 m
Total height of the tower from the ground = 22 m + 14 m = 36 m
6. Length of the monitor lizard = 2 m
Length of the python = 6 m
We know that, 6 > 2
So, Python is longer than monitor lizard.
Difference between the lengths of monitor lizard and python = 6 m – 2 m = 4 m
Thus, Python is longer than monitor lizard by 4 m.
Challenge
1. Here, 2 boxes show 10 cm.
We need to shade 1 m 30 cm
1 m 30 m = 1 m + 30 cm = 100 cm + 30 cm = 130 cm 10 cm is already shaded.
The centimetres on the metre scale that still has to be shaded = 130 cm − 10 cm = 120 cm
Since 2 boxes represent 10 cm, or 10 cm = 2 boxes 1 cm = 2 ÷ 10 boxes
120 cm will be represents by shading 120 10 × 2 = 24 blocks.
100 cm
30 cm
Do It Yourself 9B
1. a. Feather: Grams
b. Car: Kilograms
c. Pillow: Grams
1 Metre
d. Chair: Kilograms
e. Pan: Grams
f. Television: Kilograms
2. 1 kg = 1000 g
a. 8 kg = 8 × 1000 g = 8000 g
b. 9 kg = 9 × 1000 g = 9000 g
c. 1 kg 500 g = 1 × 1000 + 500 = 1000 + 500 = 1500 g
d. 4 kg 200 g = 4 × 1000 + 200 = 4000 + 200 = 4200 g
e. 3 kg 300 g = 3 × 1000 + 300 = 3000 + 300 = 3300 g
f. 7 kg 750 g = 7 × 1000 + 750 = 7000 + 750 = 7750 g
3. Weight of Farah’s pet cat = 3 kg 600 g
Weight of the pet cat in grams = 3 × 1000 + 600 = 3000 + 600 = 3600 g
Thus, the weight of Farah’s pet cat in grams is 3600 g.
4. Weight of the vegetables bought = 4 kg
Weight of the fruit bought = 5 kg
Difference between the weights of fruit and vegetables = 5 kg – 4 kg = 1 kg
Thus, Shalu purchased 1 kg more fruit than vegetables.
5. Weight of the watermelon = 5 kg
Weight of one cut piece of the watermelon = 2 kg
Weight of the other cut piece of the watermelon = 5 kg – 2 kg = 3 kg
Thus, the weight of the other piece was 3 kg.
6. Weight of the newspapers sold = 4 kg 200 g = 4 × 1000 + 200 = 4000 + 200 = 4200 g
Weight of the magazines sold = 700 g
Total weight of the scrap sold = 4200 g + 700 g = 4900 g = 4000 g + 900 g = 4 kg 900 g
Thus, the total weight of the articles was 4 kg 900 g.
Challenge
1. First weigh blocks A and B.
If the pan with block A goes down, A is heavier.
If the pan with block B goes down, B is heavier.
If A is heavier, weigh blocks A and C to find the heavier block. If B is heavier, weigh blocks B and C to find the heavier block.
Do It Yourself 9C
1. Items
a. Cough syrup
b. Syringe c. Tub of water
d. Bucket of water e. Hand sanitizer f. Barrel of water
2. 1 L = 1000 mL
a. 2 L = 2 × 1000 mL = 2000 mL
b. 6 L = 6 × 1000 mL = 6000 mL
c. 9 L = 9 × 1000 mL = 9000 mL
d. 4 L 500 mL = 4 × 1000 mL + 500 mL = 4000 mL + 500 mL = 4500 mL
e. 9 L 200 mL = 9 × 1000 mL + 200 mL = 9000 mL + 200 mL = 9200 mL
f. 5 L 850 mL = 5 × 1000 mL + 850 mL = 5000 mL + 850 mL = 5850 mL
3. Amount of water required by Rohan to make lemonade = 3 L
Amount of water required by Rohan to make lemonade in millilitres = 3 × 1000 mL = 3000 mL
4. Quantity of each water bottle = 500 mL
Number of times the water bottle is filled = 3
Total quantity of water used = 500 mL × 3 = 1500 mL = 1000 mL + 500 mL = 1 L 500 mL
Thus, Mohan used 1 L 500 mL of water.
5. Quantity of water poured in the jug = 4 L = 4 × 1000 mL = 4000 mL
Quantity of water transferred into a glass = 750 mL
Quantity of water left in the jug = 4000 mL – 750 mL = 3250 mL = 3000 mL + 250 mL = 3 × 1000 mL + 250 mL = 3 L 250 mL
Thus, 3 L 250 mL of water is left in the jug.
6. Capacity of the fuel tank of Mohit’s car = 38 L
Capacity of the fuel tank of Soham’s car = 45 L
Total capacity of the tanks of two cars
= 38 L + 45 L = 83 L
Thus, the total capacity of both tanks is 83 L.
Challenge
1. He first uses the 6 L jar to get 6 L of milk. He pours half the milk from the 6 L jar to make it 3 L of milk in total.
Chapter Checkup
1. a. Tank of water b. Spoonful of oil c. Cough syrup
d. A jug of lemonade e. Petrol tank f. Glass of juice
2. a. The length of a spoon b. The height of a tree
c. The width of a book d. The length of a swimming pool
3. a. An empty box b. A banana
c. A cylinder d. A lollipop
e. A bag of flour f. Two apples
4. a. The zip starts at 0 cm and ends at 12 cm. So, the length of the zip is 12 cm.
b. The paper clip starts at 0 cm and ends at 4 cm. So, the length of the paper clip is 4 cm.
c. The pencil starts at 0 cm and ends at 7 cm. So, the length of the pencil is 7 cm.
d. The screwdriver starts at 0 cm and ends at 8 cm. So, the length of the screwdriver is 8 cm.
5. 1 m = 100 cm
a. 5 m = 5 × 100 cm = 500 cm
b. 2 m = 2 × 100 cm = 200 cm
c. 9 m = 9 × 100 cm = 900 cm
d. 8 m 50 cm = 8 × 100 cm + 50 cm = 800 cm + 50 cm = 850 cm
e. 4 m 900 cm = 4 × 100 cm + 900 cm = 400 cm + 900 cm = 1300 cm
f. 6 m 890 cm = 6 × 100 cm + 890 cm = 600 cm + 890 cm = 1490 cm
6. 1 cm = 1 ÷ 100 m
a. 200 cm = 200 ÷ 100 = 2 m
b. 300 cm = 300 ÷ 100 = 3 m
c. 1000 cm = 1000 ÷ 100 = 10 m
d. 1100 cm = 1100 ÷ 100 = 11 m
e. 1200 cm = 1200 ÷ 100 = 12 m
f. 1300 cm = 1300 ÷ 100 = 13 m
7. 1 kg = 1000 g
a. 8 kg = 8 × 1000 g = 8000 g
b. 9 kg = 9 × 1000 g = 9000 g
c. 7 kg 450 g = 7 × 1000 + 450 g = 7450 g
d. 2 kg 999 g = 2 × 1000 + 999 g = 2999 g
e. 3 kg 760 g = 3 × 1000 + 760 g = 3760 g
f. 4 kg and 640 g = 4 × 1000 + 640 g = 4640 g
8. 1 L = 1000 mL
a. 2 L = 2 × 1000 mL = 2000 mL
b. 7 L = 7 × 1000 mL = 7000 mL
c. 4 L = 4 × 1000 mL = 4000 mL
d. 5 L 800 mL = 5 × 1000 + 800 mL = 5800 mL
e. 6 L 550 mL = 6 × 1000 + 550 mL = 6550 mL
f. 8 L 900 mL = 8 × 1000 + 900 mL = 8900 mL
9. Weight of a fully grown goliath frog = 3 kg 250 g
e. The height of a house f. The length of a room
Weight of the frog in grams = 3 × 1000 + 250 = 3000 + 250 = 3250 g
Thus, the weight of a fully grown goliath frog is 3250 grams.
10. Water used by Ahana = 5 L 500 mL = 5 × 1000 mL + 500 mL = 5000 mL + 500 mL = 5500 mL
Water used by Sameer = 1 L 200 mL = 1 × 1000 mL + 200 mL = 1000 mL + 200 mL = 1200 mL
Water saved by Sameer = 5500 mL – 1200 mL = 4300 mL = 4000 mL + 300 mL = 4 L 300 mL
Thus, Sameer saves 4 L 300 mL of water.
Challenge
1. When a ribbon is cut into 4 equal parts then 3 cuts are made. Cut 1
Cut 2 Cut 3
2.
3 m 3 m 3 m 3 m 3 m
The distance between the either ends of the trees will be 15 m.
Case Study
1. Yash uses 10 g of nuts in a mango smoothie. Thus, option (a) is correct.
2. Quantity of milk used in banana smoothie = 225 mL
Quantity of milk used in mango smoothie = 225 mL
Total quantity of milk used in both the smoothies = 225 mL + 225 mL = 450 mL
3. Weight of sugar used in the banana smoothie = 50 g
Weight of sugar used in the mango smoothie = 20 g
Total weight of the sugar used = 50 g + 20 g = 70 g
Total weight of sugar available with Yash = 1 kg = 1000 g
Total weight of sugar left with Yash after making both the smoothies = 1000 g – 70 g = 930 g
4. Answers may vary
Chapter 10
Let’s Warm-up
1.
Half past 4
Do It Yourself 10A
1. A shows the hour hand, and B shows the minute hand. B Minute hand A Hour hand
2. a. 12:00 or 12 o’ clock b. 10:15 or Quarter past 10
c. 2:30 or Half past 2
d. 12:20 or 20 minutes past 12
3. a. Sai wakes up at 7 a.m. in the morning.
b. He reaches school by 9 a.m. in the morning.
c. Sai comes back from school at 1 p.m. after noon.
d. He goes to play with his friends at 6 p.m. in the evening.
4. a. 5 minutes past 2
c. Half past 10
b. 40 minutes to 3
Quarter past 1
5. Time at which August Kranti Rajdhani Express runs between Delhi and Mumbai = 5:30 p.m.
Time at which it reaches Mumbai Central = Half past 10 in the morning
Half past 10 = 10:30
Morning means a.m.
Thus, the train reaches Mumbai Central at 10:30 a.m.
Challenge
1. Time at which Sneha reaches the lunch room = 5 minutes before 12
The time is before noon, so it will be written as 11:55 a.m.
Time at which Veena reaches the lunch room = 5 minutes after 12
The time is after noon, so it will be written as 12:05 p.m.
Thus, Sneha’s time is written as a.m., and she reached the lunch room at 11:55 a.m.
Do It Yourself 10B
1. a. The minute hand in a clock completes one round in 60 minutes.
b. The hour hand in a clock completes one round in 12 hours.
2. a. The hour hand moved from 3 to 4. It has moved by 1 number.
Since, when the hour hand moves from one number to another, the minute hand moves around the clock.
1 number = 1 hour.
So, 1 hour has passed.
b. The hour hand moved from 4 to 7. It has moved by 3 numbers.
Since, when the hour hand moves from one number to another, the minute hand moves around the clock.
1 number = 1 hour
3 numbers = 1 × 3 hour = 3 hours
So, 3 hours have passed.
c. The minute hand moved from 9 to 12. It has moved by 3 numbers.
Since, when the minute hand moves from one number to another, 5 minutes will have passed.
1 number = 5 minutes
3 number = 3 × 5 = 15 minutes
So, 15 minutes have passed.
d. The hour hand moved from 3 to 5. It has moved by 2 numbers.
d.
The minute hand moved from 9 to 12. It has moved by 3 numbers.
So, 2 hours and 15 minutes have passed.
3. a. Filling a glass of milk will take some minutes.
b. Watering a plant will take some minutes.
c. Eating a banana will take a few minutes.
d. Washing, ironing and folding clothes will take an hour or more.
4. Time taken to complete the marathon = 2 hours
We know that, 1 hour = 60 minutes
Number of minutes taken to complete the marathon = 2 × 60 minutes = 120 minutes
Thus, Eliud Kipchoge completed the marathon in around 120 minutes at the Berlin Marathon.
5. Start time of Shatabdi Express from Delhi = 6:45 a.m.
Time at which Shatabdi Express reached Meerut = 8:00 a.m.
From 6:45 a.m. to 8:00 a.m., the hour hand has moved 1 number and the minute hand moved 3 numbers. So, 1 hour and 15 minutes has passed.
We know that 1 hour = 60 minutes
Thus, Vibhu took 60 + 15 = 75 minutes to reach to Meerut from Delhi.
Challenge
1. Given that, = 1 hour and = 10 minutes
We need to represent 160 minutes using these symbols. 160 minutes = 120 minutes + 40 minutes
We know that, 1 hour = 60 minutes
120 minutes = 120 ÷ 60 = 2 hours
So, 160 minutes = 2 hours + 40 minutes
Using the symbols, 160 minutes can be represented as .
Do It Yourself 10C
1. a. 2024 Day of the week
b. January Month
c. 26th Year
d. Friday Date of the month
2. a. Sunday is a month. False, because Sunday is a day.
b. December is a month. True
c. May is the first day of the week. False, because May is a month not a day and it is the fifth month of the year.
d. A leap year has 29 days in February True
3. a. There are 4 Sundays in this month.
b. The month starts from a Monday
c. On 25 May, the day is Thursday
d. 2 May is a Tuesday. The next Tuesday will be on 9 May.
e. In this month, Saturdays are on dates 6, 13, 20 and 27
4. We know that, 1 week = 7 days
So, 2 weeks = 7 + 7 OR 2 × 7 = 14 days
Thus, Anand has practiced his dance performance for 14 days.
6. Date on which Constitution of India was adopted by the Constituent Assembly = 26 November, 1949
Date on which Constitution of India was implemented = 26 January, 1950
Number of months taken for the implementation of Constitution of India = 2 months
26 November 1949 26 December 1949 26 January 1950 1 month 1 month
Challenge
1. We need to find the number of leap years between 2014 and 2058.
The first leap year after 2014 is 2016.
A leap year comes after every 4 years. The leap years will be 2016, 2020, 2024, 2028, 2032, 2036, 2040, 2044, 2048, 2052 and 2056.
Thus, there are 11 leap years between 2014 and 2058.
Do It Yourself 10D
1. Navratri
Starts Dusshera Diwali Bhai Dooj Guru Nanak Jayanti
3 October 12 October 1 November 3 November 27 November
2. Cricket match Basketball match Tug-of-war match Football match Kho-Kho match
February August October November December
3. a. Rina was born in the year 2000.
b. The year in which Rina was born = 2000
Year in which Rina’s sister was born = 2007
Rina’s age at the time of her sister’s birth = 2007 – 2000 = 7 years
Thus, Rina was 7 years at the time of her sister ’s birth.
c. The year in which Rina won the dance competition = 2015
Age of Rina when she won the dance competition = 2015 – 2000 = 15 years
Thus, Rina was 15 years old when she won the dance competition.
d. Age of Rina in 2034 = 2034 – 2000 = 34 years
Thus, Rina will be 34 years old in 2034.
4. Birthdate of Tinu = 31 July 2015
Birthdate of Mitu = 31 July 2021
Since, 2015 < 2021, Tinu was born earlier, he is older than Mitu.
Difference between the ages of Tinu and Mitu = 2021 – 2015 = 6 years
Thus, Tinu is older than Mitu by 6 years.
Challenge
1. Suppose Seema’s brother’s age = B
Seema’s age = 2 times the brother’s age = 2 × B
Seema’s age = 10 + Brother’s age = 10 + B
10 + B = 2 × B
10 = 2 × B − B
10 = B
5.
So, B = 10
Seema's age = 2 × B = 2 × 10 = 20
Thus, Seema’s age is 20 years and her brother’s age is 10 years.
Chapter Checkup
1. a.
50 minutes past 1 or 1:50 or 10 minutes to 2
b. Half past 1 or 1:30
c. Quarter to 11 or 10:45
2. a. 10 minutes past 12
b. Half past 1
c. Quarter to 7
3. a. Between 5:20 and 7:20, the hour hand has moved 2 numbers.
So, 2 hours have passed.
b. Between 9:15 and 11:15, the hour hand has moved 2 numbers.
So, 2 hours have passed.
c. Between 2:10 and 4:10, the hour hand has moved 2 numbers.
So, 2 hours have passed.
4. a. 7:30 in the morning is after midnight and before noon.
So, it is 7:30 a.m.
b. 6:15 in the evening is after 12 o’ clock in the noon but before midnight 12 o’ clock.
So, it is 6:15 p.m.
c. 5 minutes to 12 midnight can be written as 11:55. It is before 12 o’ clock midnight. So, it is 11:55 p.m.
d. 5 minutes after 12 midnight can be written as 12:05. It is after midnight 12 o’ clock.
So, it is 12:05 a.m.
5. a. Making tea will take some minutes.
b. Washing a shirt will take some minutes.
c. Blinking eyes 5 times will take less than a minute.
d. A picnic day will take hours.
6. a. The date on the last day of the year is always 31 December.
b. If today is 30 April 2023, the date tomorrow will be 1 May, 2023, because April has 30 days.
c. If today is 12 June 2023, yesterday’s date was 11 June, 2023.
d. If today is Monday, 1 June 2023, the date after a week will be Monday, 8 June 2023, because 1 week = 7 days. So, 1 + 7 = 8
7. Born in Delhi Played for Delhi U-15 U-19 England Tour Won U-19 World Cup Won ODI World Cup
5
8. Sun Mon Tues Wed Thurs Fri
a. There are 5 Sundays in the month.
b. The date on the 2nd Saturday is 14.
c. The dates of all the Mondays are 2, 9, 16, 23, 30.
9. Time at which Rama woke up = 7 o’ clock in the morning 7 o’ clock in the morning is after 12 o’ clock midnight but before noon 12 o’ clock.
So, Rama woke up at 7 a.m.
Time at which Rama slept = 9 o’ clock in the night
9 o’ clock at night is after noon and before midnight 12 o’ clock.
So, Rama slept at 9 p.m.
10. Aditi’s age on 28 August 2007: 7 years.
7 + 7 = 14
Thus for 14 years, we add more 7 years to the date: 2007 + 7 = 2014
Thus, Aditi was 14 years old on 28 August 2014.
Challenge
1. Today’s date: 17 April 2023
As the month and year will remain the same, the date from 5 days from now will be 17 + 5 = 22 April 2023
Today is Monday. It will be Saturday after 5 days.
Thus, Arun’s uncle will come on Saturday, 22 April 2023.
2. Number of times hour hand minute hand coincide between 3 p.m. and 4 p.m. = 1 time
Number of times hour hand minute hand coincide between 4 p.m. and 5 p.m. = 1 time
Number of times hour hand minute hand coincide between 5 p.m. and 6 p.m. = 1 time
Thus, the hour hand and the minute hand coincide 3 times between 3 p.m. and 6 p.m.
Case Study
1. The train was delayed by 50 minutes.
2. When Priya reached the station, the clock was showing 3:00 p.m.
When Priya reached there were still 50 minutes for her train to leave.
So, the actual time of Priya’s train was 3:50 p.m.
Thus, option b is correct.
3. The train got delayed by 50 minutes. The original time of arrival was 3:50 p.m.
The time at which the train arrived = 3:50 p.m. + 50 minutes = 4:40 p.m.
Thus, the train arrived at 4:40 p.m.
4. The train was delayed by 50 minutes. So, it was not delayed by an hour. Since 1 hour = 60 minutes
5. Time taken by sweeper to clean the platform = 1 hour 1 hour = 60 minutes
So, the sweeper cleaned the platform in 60 minutes. Answer may vary.
Chapter 11
Let’s Warm-up
1. We can get two ₹10 notes or coins for ₹20, since 2 × ₹10 = ₹20
2. We can get six ₹5 coins for ₹30, since 6 × ₹5 = ₹30
3. Seven ₹2 coins and one ₹1 coin make ₹15, since 7 × ₹2 + 1 × ₹1 = ₹14 + ₹1 = ₹15
4. Ten ₹2 coins make ₹20, since 10 × ₹2 = ₹20
Do It Yourself 11A
1. a. ₹28.50 - Twenty-eight rupees fifty paise
b. ₹36.25 - Thirty-six rupees twenty-five paise
c. ₹49.70 - Forty-nine rupees seventy paise
d. ₹57.35 - Fifty-seven rupees thirty-five paise
e. ₹65.37 - Sixty-five rupees thirty-seven paise
f. ₹71.75 - Seventy-one rupees seventy-five paise
g. ₹88.62 - Eighty-eight rupees sixty-two paise
h. ₹92.48 - Ninety-two rupees forty-eight paise
2. a. Fifty-six rupees seventy paise = ₹56.70
b. Twenty-nine rupees eighty-eight paise = ₹29.88
c. Thirty-five rupees fifty-seven paise = ₹35.57
d. Sixty-eight rupees fifty paise = ₹68.50
e. Seventy-three rupees twenty-two paise = ₹73.22
f. Fifteen rupees sixty-six paise = ₹15.66
3. a.
₹32.50
4. a. ₹25.36 = 2536 paise
b. 802 paise = ₹8.02
c. 2125 paise = ₹21.25
d. ₹125.36 = 12536 paise
e. 36125 paise = ₹361.25
f. ₹358.80 = 35880 paise
5. Price of petrol in Mumbai as of July 2024 = ₹103.44 ₹103.44 as words is one hundred three rupees forty-four paise.
6. Mahi’s Gullak: One note of ₹50, one note of ₹20, coins of ₹10, ₹5 and ₹5
Total amount in Mahi’s Gullak = ₹50 + ₹20 + ₹10 + ₹5 + ₹5 = ₹90
Meher ’s Gullak: Three notes of ₹20 and one coin of ₹10
Total amount in Meher’s Gullak = 3 × ₹20 + ₹10 = ₹60 + ₹10 = ₹70
Mahi’s Gullak has ₹20 more than Meher’s Gullak. Half of this money should be transferred to Meher’s Gullak so that they have the same amount of money.
Thus, ₹20 ÷ 2 = ₹10 should be transferred.
Mahi can transfer two coins of ₹5 or one coin of ₹10 to Meher’s Gullak.
Challenge
1. We need to make ₹639 with the help of 3 notes and 4 coins. We can take 1 of ₹500, 1 note of ₹100 and 1 note of ₹20; 1 coin of ₹10, 1 coin of ₹5 and 2 coins of ₹2. ₹500 + ₹100 + ₹20 + ₹10 + ₹5 + (2 × ₹2) = ₹639
Do It Yourself 11B
1. Price of the lunch box = ₹85.50
Amount of money Priya has = ₹72
More money required by Priya to buy the lunch box = ₹85.50 − ₹72 = ₹13.50
2. Money saved by Vaibhav = ₹50.50
Money saved by Neeraj = ₹75.00
Total money saved by Vaibhav and Neeraj = ₹50.50 + ₹75.00 = ₹125.50
3. Price of the cricket bat = ₹235.50
Price of the ball = ₹45.00
Total price of the bat and the ball = ₹235.50 + ₹45.00 = ₹280.50
4. Cost of snake plant = ₹238
Cost of money plant = ₹125.50
Total money spent = ₹238 + ₹125.50 = ₹363.50
5. Amount of money John has = ₹284.50
Amount of money Maria has = ₹156.00
Amount of money Richa has = ₹284.50 – ₹156.00 = ₹128.50
Richa has ₹128.50 with her
6 Amount given to the shopkeeper = ₹100 Amount received back = ₹28.50 Cost of pencil box = ₹100 – ₹28.50 = ₹71.50 The cost of the pencil box is ₹71.50.
Do It Yourself 11C
1. Fruits and Veggies Store
Vipin needs to pay ₹96.50.
2. The bill is not correct. The correct bill is:
4. Ravi Buys Joe Buys Tanya Buys 2 bananas for ₹10.00
Total:
Yes, Sahil will be able to purchase all the fruits.
Chapter Checkup
1. a. ₹52.36 = Fifty-two rupees thirty-six paise
b. ₹65.14 = Sixty-five rupees fourteen paise
c. ₹71.05 = Seventy-one rupees five paise
2. a. Thirty-eight rupees sixty-five paise = ₹38.65
b. Twenty-nine rupees fifty-five paise = ₹29.55
3. To convert rupee amount to paise amount, remove the dot and ₹ sign then write paise with the number.
a. ₹25.15 = 2515 paise
b. ₹52.25 = 5225 paise
c. ₹235.48 = 23548 paise
4. To convert the paise amount to rupee amount, remove the word 'paise' and put a dot after counting 2 numbers from the right of the given number then put the sign of ₹ before the number.
a. 3256 paise = ₹32.56
b. 15236 paise = ₹152.36
c. 52364 paise = ₹523.64
5. Remove the dot and ₹ sign then write paise with the number. In rupees In paise
a. ₹2.35 348 paise
b. ₹3.48 3480 paise
c. ₹23.56 235 paise
d. ₹34.80 2356 paise
6. Correct bills:
Challenge
1. Amount with Sahil—₹200 Let us prepare the bill for Sahil. Super Market Item Quantity Rate per Item Amount Apples 4 ₹20.00 ₹80.00
Divya has to pay ₹188.50.
8. Cost of a pack of cupcake = ₹136.50
Cost of sugar used in the cupcake = ₹55
Cost of other ingredients used in the cupcake
9. Money that has to be paid by Reena for school fees = ₹535.50
Money with Reena = ₹425
More money required by Reena = ₹535.50 – ₹425 = ₹110.50
10. Amount donated at a mall = ₹152.00
Amount donated outside the temple = ₹58.50
Total amount donated = ₹152.00 + ₹58.50 = ₹210.50
Challenge
1. Store
Amount customer paid to Sam = ₹200.00
Amount Sam will return = ₹200 – ₹130 = ₹70
2. Money with Ajay = ₹2 + ₹1 + 50 paise + 50 paise + 50 paise = ₹3 + ₹1 + 50 paise = ₹4 and 50 paise = ₹4.50
Money with Rahul = ₹2 + ₹2 + ₹1 + 50 paise = ₹5 and 50 paise = ₹5.50
Difference between the amount of money with Ajay and Rahul = ₹5.50 – ₹4.50 = ₹1
Thus, Rahul has ₹1 more than Ajay in his pocket.
Case Study
1. 1 rupee = 100 paise
1 paisa = 10 kauri
1 rupee = 100 × 10 kauri
= 1000 kauri
Thus, option d is correct.
2. Cost of a toy = 10 paise
10 paise as kauri = 10 × 10 kauri
= 100 kauri
Thus, the toy costs 100 kauri.
3. 1 rupee = 100 paise
5 rupees = 5 × 100 paise
= 500 paise
Thus, 5 rupees is the same as 500 paise.
4. Answers may vary.
Chapter 12
Let’s Warm–up
Do It Yourself 12A
1. a. Since 1 out of 2 parts are shaded, the fraction for the shaded portion is 1 2
b. Since 1 out of 3 parts are shaded, the fraction for the shaded portion is 1 3
c. Since 1 out of 4 parts are shaded, the fraction for the shaded portion is 1 4
2. The coloured part of the whole may vary. Sample answers:
a. Half or 1 2 b. Three-fourth or 3 4 c. One-third or 1 3
One-fourth or 1 4 e. Two-thirds or 2 3 f. Three-fourths or 3 4
4. To shade 1 3 of a shape, any one part of 3 parts is to be shaded. Sample figures: a. b. c.
5. Total cups of water that was boiled = 4 cups Cups of water that got evaporated = 2 cups Fraction of water that turned into water vapour = 2 4
Challenge
1. Rajiv folded the paper in half three times. Each time you fold a paper in half, the number of equal parts doubles.
First fold: The paper is folded in half, so there are 2 equal parts.
Second fold: The paper is folded in half again, doubling the parts to 4 equal parts.
Third fold: The paper is folded in half once more, doubling the parts again to 8 equal parts.
After unfolding the paper, it will be divided into 8 equal parts. Since Rajiv coloured each part differently, the fraction representing each part is 1 8
Thus, each of the 8 equal parts represents 1 8 of the whole sheet.
Do It Yourself 12B
1. a. To shade 1 2 of the total objects, any half of the total number of objects can be shaded.
Sample answer:
Total number of pumpkins = 16
Part of the collection we want to colour = half or 1 2
Half or 1 2 of the collection = 16 ÷ 2 = 8
b. To shade 1 2 of the total objects, any half of the total number of objects can be shaded.
Sample answer:
Total number of bats = 14
Part of the collection we want to colour = half or 1 2
Half or 1 2 of the collection = 14 ÷ 2 = 7
c. To shade 1 3 of the total objects, any one-third of the total number of objects can be shaded.
Sample answer:
Total number of mangoes = 18
Part of the collection we want to colour = one-third or 1 3
One-third or 1 3 of the collection = 18 ÷ 3 = 6
d. To shade 1 4 of the total objects, any quarter of the total number of objects can be shaded.
Sample answer:
Total number of apples = 16
Part of the collection we want to colour = one-fourth or 1 4
One-fourth or 1 4 of the collection = 16 ÷ 4 = 4
2. a. 1 4 of 16 = 16 ÷ 4 = 4. So, the statement is true.
b. 1 2 of 10 = 10 ÷ 2 = 5. So, the statement is false.
c. 1 3 of 6 = 6 ÷ 3 = 2. So, the statement is false.
d. 1 3 of 18 = 18 ÷ 3 = 6; 2 3 of 18 = 2 × 6 = 12. So, the statement is false.
3. a. To find 1 2, we divide the whole by 2.
1 2 of 18 = 18 ÷ 2 = 9
b. To find 1 3, we divide the whole by 3.
1 3 of 9 = 9 ÷ 3 = 3
c. To find 1 3, we divide the whole by 3.
1 3 of 21 = 21 ÷ 3 = 7
d. To find 1 4, we divide the whole by 4.
1 4 of 12 = 12 ÷ 4 = 3
4. Total number of plants = 12
Fraction of plants that were put in the living room = 1 3
Number of plants that were put in the living room = 1 3 of 12 = 12 ÷ 3 = 4
Thus, 4 plants were put in the living room.
5. Figures may vary. Sample figure:
Fraction = 8 16
8 parts out of 16 parts are shaded, so the fraction is 8 16
Challenge
1. Total number of bears in the zoo = 12
Fraction of bears which are brown = 1 3
Number of brown bears in the zoo = 1 3 of 12 = 12 ÷ 3 = 4
Number of black bears in the zoo = 2 × 4 = 8
Number of black bears and brown bears in the zoo
= 4 + 8 = 12
= Total number of bears in the zoo. Thus, there are no other colour bears in the zoo.
Do It Yourself 12C
1. a. Total number of parts = 8
Number of shaded parts = 4
Fraction of shaded parts = Number of shaded parts
b. Total number of parts = 9
Number of shaded parts = 5
Total number of parts = 4 8
Fraction of shaded parts = Number of shaded parts
c. Total number of parts = 9
Number of shaded parts = 4
Total number of parts = 5 9
Fraction of shaded parts = Number of shaded parts
d. Total number of parts = 16
Total number of parts = 4 9
Number of shaded parts = 7
Fraction of shaded parts = Number of shaded parts
Total number of parts = 7 16
2. a. 8 out of 14 parts are to be shaded.
8 14
b. 4 out of 10 parts are to be shaded.
4 10
c. 6 out of 10 trees are to be shaded. 6 10
d. 5 out of 9 tomatoes are to be shaded. 5 9
3. a. Total parts in the collection = 9
Number of coloured parts = 4
Fraction of coloured part: Number of coloured parts
Total parts = 4 9
Number of uncoloured parts = 5
Fraction of uncoloured part:
Number of uncoloured parts
Total parts = 5 9
b. Total parts in the collection = 9
Number of coloured parts = 3
Fraction of coloured part: Number of coloured parts
Number of uncoloured parts = 6
Total parts = 3 9
Fraction of uncoloured part: Number of uncoloured parts
Total parts = 6 9
c. Total parts in the collection = 11
Number of coloured parts = 6
Fraction of coloured part: Number of coloured parts
Number of uncoloured parts = 5
Total parts = 6 11
Fraction of uncoloured part: Number of uncoloured parts
Total parts = 5 11
d. Total parts in the collection = 13
Number of coloured parts = 6
Fraction of coloured part: Number of coloured parts
Number of uncoloured parts = 7
Total parts = 6 13
Fraction of uncoloured part: Number of uncoloured parts
Total parts = 7 13
4. Number of red roses = 8
Total number of roses in the vase = 17
Fractions of red roses in the vase = Number of red roses
Total number of roses = 8 17
5. Number of bottles thrown away as waste = 24
Fraction of bottles which were plastic = 1 2
Number of bottles which were plastic = 1 2 of 24 = 24 ÷ 2 = 12
Thus, there were 12 plastic bottles.
6. Total number of shirts with Vishal = 12 shirts
Fraction of shirts which were blue = 1 4
Number of shirts which were blue = 1 4 of 12 = 12 ÷ 4 = 3
Thus, Vishal had 3 blue shirts.
7. Total number of building blocks in the bag = 25
Number of blocks used by Ravi to build a house = 16
Number of blocks which remain unused = 25 – 16 = 9
Fraction of building blocks which remain unused =
Number of unused blocks
Total number of blocks = 9 25
8. Total number of books with Rani = 27
Fraction of books donated by Rani = 1 3
Number of books donated by Rani = 1 3 of 27 = 27 ÷ 3 = 9
Number of books left with Rani = 27 – 9 = 18
Thus, Rani is left with 18 books.
Challenge
1. 4 parts out of 5 is equal to 16.
Thus, 5 parts will be 20.
Thus, there are 20 buses in total.
The figure below shows the groups of buses and buses in each group.
2. Let us divide the shape into equal parts as shown in the figure.
Total number of equal parts = 10
Total number of shaded parts = 2
Total number of unshaded parts = 8
Fraction of the shape left unshaded = 8 10
Chapter Checkup
1. a. Half = 1 2
b. One-third = 1 3
c. Three-fourths = 3 4
d. Numerator: 5; Denominator: 8 = 5 8
e. One-fourth = 1 4
f. Numerator: 7; Denominator: 12 = 7 12
2. a. Total capsicum in the collection = 12
Number of green capsicum = 5
Fraction of green capsicum = Number of green capsicum
Total capsicum = 5 12
Number of yellow capsicum = 7
Fraction of yellow capsicum = Number of yellow capsicum
Total capsicum = 7 12
b. Total stars in the collection = 17
Number of pink stars = 9
Fraction of pink stars = Number of pink stars
Total number of stars = 9 17
Number of blue stars = 8
Fraction of blue stars = Number of blue stars
Total number of stars = 8 17
3. The coloured part of the whole may vary.
a. 3 5
b. 2 7
c. Total kites = 18; Fraction of the kites to be shaded = 1 2 of the total kites = 1 2 of 18 = 18 ÷ 2 = 9
So, we will shade 9 kites.
d. Total balls = 21; Fraction of balls to be shaded = 1 3 of the total balls = 1 3 of 21 = 21 ÷ 3 = 7
So, we will shade 7 balls.
4. a. To find 1 2 of 12, we divide the number by 2: 12 ÷ 2 = 6
b. To find 1 3 of 15, we divide the number by 3: 15 ÷ 3 = 5
c. To find 1 4 of 4, we divide the number by 4: 4 ÷ 4 = 1
d. To find 1 2 of 8, we divide the number by 2: 8 ÷ 2 = 4
5. Total number of people = 4 friends + Tim = 5 friends
Number of equal parts cake is divided = 5
Since the cake is divided into 5 equal parts and there are 5 people, each person gets one part of the cake.
So, the number of pieces each friend gets = 1
Fraction of cake that each friend gets =
Number of parts each friend gets
Total number of parts = 1 5
Thus, each friend gets 1 5 of a cake.
6. Total number of flowers bought by Meena = 9
Fraction of flowers that were tulips = 1 3
Number of flowers that were tulips = 1 3 of 9 = 9 ÷ 3 = 3 tulips
Thus, Meena bought 3 tulips.
7. Total number of plants planted by Manya = 6 plants
Number of plants which were rose = 2 plants
Fraction of plants which were rose = 2 6
8. Total number of apples = 24
Fraction of apples that were rotten = 1 4
Number of apples that were rotten = 1 4 of 24 = 24 ÷ 4 = 6
Number of apples which are still good = 24 – 6 = 18
Thus, 18 apples are still good.
9. Number of invitations sent = 18
Number of friends who were not able to attend the birthday party = 3
Number of friends who attended the birthday party = 18 – 3 = 15
Fraction of friends who attended the birthday party = 15 18
Thus, 15 18 friends attended the birthday party.
Challenge
1. Clue: I am less than 2 and a half wholes. I am more than a whole. You can make me out of 4 halves.
4 halves is the same as 2 wholes.
In option A, we can see two wholes.
Thus, the correct answer is A.
2. Answers may vary. Sample figures:
Case Study
1. Total parts = 8
Parts for fruits and vegetables = 3
Fraction filled with fruits and vegetables = 3 8
Thus option c is correct.
2. Total parts = 8
Parts for proteins = 3
Fraction of proteins in the plate = 3 8
3. Grains cover 2 8 of the plate. True 3 4 of the plate is proteins. False
4. Total parts = 8
Parts of the plate that are protein = 3
Parts of the plate that are not protein = 8 − 3 = 5
Fraction of the plate that is not protein = 5 8
5. Answers may vary.
Chapter 13
Let’s Warm-up
1. Tuesday 2. Friday
3. Monday and Wednesday 4. Thursday
Do It Yourself 13A
1. a. Raw data is an organised form of data. False
b. Writing the numbers in ascending or descending order makes it easier to find the greatest or smallest from the data. True
c. Collecting data makes it easy to understand. False
d. The data collected from surveys is called raw data. True
2. Data of marks obtained out of 100 in Maths, organised from highest to lowest: 99, 98, 89, 83, 80, 78, 77, 70, 65, 58, 45
3. Let us put the data in the table form: Apple, Orange, Banana, Mango, Apple, Grapes, Banana, Grapes, Apple, Grapes, Banana, Mango, Apple, Grapes, Mango, Apple, Banana, Grapes, Mango, Banana, Apple, Orange, Mango, Orange, Grapes, Banana, Orange, Mango.
4. a. The number of people who eat barley is 3
b. The number of people who eat ragi is less than those who eat rice.
c. The most people eat rice as their main food.
Challenge
1. a. Number of cutlets sold by shop A in Week 5
= Half the number of cutlets sold in Week 4
= 1 2 × 40 = 40 ÷ 2 = 20
Thus, shop A sold 20 cutlets in Week 5.
b. Number of cutlets sold by shop B in Week 2 if it sells 10 more cutlets = 40 + 10 = 50
Number of cutlets sold by shop B in Week 3 if it sells 10 more cutlets = 30 + 10 = 40
Total number of cutlets sold by shop B in Week 2 and Week 3 = 50 + 40 = 90
Total number of cutlets sold by shop A in Week 2 and Week 3 = 50 + 20 = 70
Difference between the number of cutlets sold by shop A and shop B in Week 2 and Week 3 = 90 – 70 = 20
Thus, shop B sold 20 more cutlets than shop A in these Weeks.
Do It Yourself 13B
1. a. A pictograph represents data using pictures and objects. True
b. In a pictograph, more pictures mean a bigger number.
True
c. Pictographs help us understand and interpret the data.
True
2. = 2 children. We can break the given numbers in the multiplication tables of 2.
Favourite Swings Number of Children Favourite Swings Number of Children
2 × 6 = 12
2 × 5 = 10
2 × 4 = 8
3. Given that, = 2 books
Thus,
a. In the table, the number of symbols given for Wednesday = 4
Number of books borrowed on Wednesday = 4 × 2 = 8 books
b. The day on which there are maximum number of symbols = Friday
Number of symbols on Friday = Five and a half
Number of books borrowed on Friday = 5 × 2 + 1 2 × 2
= 10 + (2 ÷ 2) = 10 + 1 = 11
c. Number of symbols on Tuesday = Three and a half
Number of books borrowed on Tuesday = 3 × 2 + 1 2 × 2
= 6 + 1 = 7
Number of symbols on Thursday = 3
Number of books borrowed on Thursday = 3 × 2 = 6
Difference between the number of books borrowed on Tuesday and Thursday = 7 – 6 = 1
4. Flavour Number of Ice Creams
Vanilla
Strawberry
Chocolate
Mango
Key: = 1 ice cream
5. Given that, Key: 1 bin = 1 unit
a. Number of symbols for wet waste = 5
Number of households who segregate wet waste = 5 × 1 = 5 households
Number of symbols for e-waste = 4
Number of households who segregate e-waste = 4 × 1 = 4 households
Difference between the number of households who segregate wet waste and e-waste = 5 – 4 = 1
Thus, 1 more household segregate wet waste compared to e-waste.
b. Number of symbols for wet waste = 5
Number of households who segregate wet waste = 5 × 1 = 5 households
If 3 more households start segregating wet waste then the number of households who segregate wet waste = 5 + 3 = 8 households
c. Answers may vary
6. Answers may vary. Sample answer: On how many households was the survey conducted?
Challenge
1. a. Here, 1 = 10 animals or 10 animals = 1
1 animal = 1 ÷ 10
50 animals = 1 10 × 50 = 5
So, pictures will represent 50 animals.
So, if = 10 animals, 5 pictures will be drawn for 50 animals.
b. Here, 2 = 10 snowflakes
So, = 10 ÷ 2 = 5 snowflakes
20 snowflakes = 5 snowflakes × 4
So, will represent 20 snowflakes.
So, if 2 = 10 snowflakes, 4 pictures will be drawn for 20 snowflakes.
3. a. The least number of glasses of water were drank by Raghav and Eric.
The most number of glasses of water were drank by Nimisha.
b. Number of glasses of water which Nimisha drank = 9
Number of glasses of water which Rajat drank = 8
Difference between the number of glasses of water drank by Nimisha and Rajat = 9 – 8 = 1
Thus, Nimisha drank 1 more glass of water than Rajat.
c. Number of glasses of water which Raghav drank = 7
Number of glasses of water which Shoaib drank = 8
Difference between the number of glasses of water drank by Raghav and Shoaib = 8 – 7 = 1
Thus, Raghav drank 1 less glass of water than Shoaib.
4. a. 4 children like sports.
b. Cartoon channel is the favourite. 9 children like it.
c. Number of children who like adventure = 5
Number of children who like sports = 4
The difference between the number of children who like sports and the number of children who like adventure = 5 – 4 = 1 child
d. Number of children who like comedy = 8
Number of children who like sports = 4
Number of children who like cartoons = 9
Number of children who like adventure = 5
Total number of children in the survey = 8 + 4 + 9 + 5 = 26 children
5. Answers may vary. Sample answer: How many more students like comedy than adventure?
Challenge
1. a. Number of students who read ‘Red Riding Hood’ = 4
If 2 more students read ‘Red Riding Hood’ then the number of students who read this book = 4 + 2 = 6
The book which is read by 6 students according to the given bar graph = ‘Town Mouse and Country Mouse’
Thus, if 2 more students read the story, ‘Red Riding Hood’ then ‘Red Riding Hood’ and ‘Town Mouse and Country Mouse’ will show the same bars.
b. Given that, new 1 division = 2 books.
Earlier 1 division = 1 book
Number of books for ‘Beauty and the Beast’ = 10 books
When 1 division = 2 books, then 10 books will be represented by 10 ÷ 2 = 5 divisions.
Thus, if the scale shows 1 division = 2 books, then we will show 5 divisions for ‘Beauty and the Beast’.
Chapter Checkup
1. Favourite Fruit Number of Students
Number of People in a Household
2. Favourite Hobby Number of Students Singing Dancing Sports Watching TV Reading
3. Given: 1 CINEMA TICKET... = 2 students
a. Number of symbols for musical films = 10
Number of children whose favourite genre is musical = 10 × 2 = 20 children
b. The genre which has the least number of symbols = Action
Thus, action films is liked by the least number of children.
c. Number of symbols for musical films = 10
Number of children whose favourite genre is musical = 10 × 2 = 20 children
Number of symbols for action films = 8
Number of children whose favourite genre is action = 8 × 2 = 16 children
Difference between the number of children who like musical films and those who like action films = 20 – 16 = 4 children
Thus, 4 more children like musical films than action films.
4. a. Only 1 run is scored in the 5th over.
b. Maximum runs were scored in the 6th over.
c. List and add the runs scored in each over till the 10th over: 4 + 8 + 9 + 3 + 1 + 10 + 6 + 8 + 9 + 5 = 63
63 runs are scored in 10 overs.
Challenge
1. As there are 4 pictures of squirrel and 1 picture of squirrel = 2 squirrels then 4 pictures = 4 × 2 = 8 squirrels
Thus, 8 squirrels visited Meher’s garden on Sunday.
2. a. Number of symbols of tomatoes for Suresh = 5 and a half If 2 tomatoes are removed then the number of symbols of tomatoes for Suresh = 3 and a half
Number of tomatoes with Suresh = 3 × 2 + 1 2 × 2 = 6 + 1 = 7 tomatoes
Thus, if 2 pictures of tomatoes are removed from Suresh’s row, then 7 tomatoes were used by him.
b. New key: 1 picture = 4 tomatoes
Old key: 1 picture = 2 tomatoes
Number of tomatoes with Tarachand as per old key = 4 × 2 = 8 tomatoes
Number of pictures of tomatoes for Tarachand as per new key = 8 tomatoes ÷ 4 = 2 pictures
Thus, if the key changes to 1 picture = 4 tomatoes, then 2 pictures should be drawn for Tarachand.
Case Study
1. The highest rainfall is in the month of February. Thus, the correct answer is option (c).
2. The bar for June is the lowest. June shows the lowest rainfall.
3. April has the second highest length of the bar in the bar graph. Thus, April shows the second highest rainfall.
4. Answers may vary.