Workbook Prathomsuksa 6 © Pelangi Publishing (Thailand) Co., Ltd. 2022 All rights reserved. No part of this publication may be reproduced, stored in any retrieval system or transmitted in any form or by any means without permission of Pelangi Publishing (Thailand) Co., Ltd. 2022
BJRC366031_GoGetMaths WB Prelimpage P6.indd 1
885-87220-0364-7 First Published 2022
29/1/2565 BE 13:40
Contents Chapter 1
Chapter 2
Chapter 3
Chapter 4
Chapter 5
Chapter 6
Revision 1
Content SG Maths WB P6 page ii.indd 2
Factors and multiples
1
Practices
Chapter 7
Triangles
115
1
Practices
115
Think
20
Think
131
Fractions
21
Polygons
132
Practices
21
Practices
132
Think
39
Think
144
Decimals
40
Circles
145
Practices
40
Practices
145
Think
54
Think
163
Ratios
55
Volume and capacity
164
Practices
55
Practices
164
Think
68
Think
178
Percentages
69
Solids
179
Practices
69
Practices
179
Think
88
Think
188
Patterns
89
Pie charts
189
Practices
89
Practices
189
Think
104
Think
197
105
Chapter 8
Chapter 9
Chapter 10
Chapter 11
Chapter 12
Revision 2
198
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Chapter 1 Factors and multiples Practice 1
Factors
1. Determine if each number is a factor of the number in the brackets. .g .
4 (60)
a 5 (35)
60 ÷ 4 = 15
35 ÷ 5 = 7
So, 4 is a factor of 60.
So, 5 is a factor of 35.
b 8 (104)
c
104 ÷ 8 = 13
123 ÷ 11 = 11 R 2
So, 8 is a factor of 104.
So, 11 is not a factor of 123.
d 9 (73)
e
73 ÷ 9 = 8 R 1
300 ÷ 25 = 12
So, 9 is not a factor of 73.
So, 25 is a factor of 300.
11 (123)
25 (300)
2. List the factors of these numbers.
.g .
8
1, 2, 4, 8
a
15
1, 3, 5, 15
b
24
1, 2, 3, 4, 6, 8, 12, 24
c
35
1, 5, 7, 35
d
56
1, 2, 4, 7, 8, 14, 28, 56
e
78
1, 2, 3, 6, 13, 26, 39, 78
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3. Determine if each of the following is a prime number. .g .
11 11 cannot be divided by 2, 3, 5 and 7 exactly. 11 has only 2 factors, 1 and 11. So, 11 is a prime number.
b 37 37 cannot be divided by 2, 3, 5, 7, 11, 13, 17, 19 and 23. 37 has only 2 factors, 1 and 37. So, 37 is a prime number.
a 26 26 ÷ 2 = 13 26 has more than 2 factors. So, 26 is not a prime number.
c
35 35 ÷ 5 = 7 35 has more than 2 factors. So, 35 is not a prime number.
4. List all the prime factors of each of the following. .g .
18 Factors of 18 = 1, 2, 3, 6, 9, 18 Prime factors of 18 = 2, 3
b 39 Factors of 39 = 1, 3, 13, 39 Prime factors of 39 = 3, 13
a 28 Factors of 28 = 1, 2, 4, 7, 14, 28 Prime factors of 18 = 2, 7
c
70 Factors of 70 = 1, 2, 5, 7, 10, 14, 35, 70 Prime factors of 70 = 2, 5, 7
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5. Express the following numbers in the form of prime factorization using repeated short division. Express the answers in index notation. .g .
52
a 70
2 52 2 26 13 13 1
2 70 5 35 7 7 1
52 = 2 × 2 × 13 = 22 × 13
b 108
70 = 2 × 5 × 7
c
2 108 2 54 3 27 3 9 3 3 1
2 200 2 100 2 50 5 25 5 5 1
108 = 2 × 2 × 3 × 3 × 3 = 22 × 33 d 270 2 270 3 135 3 45 3 15 5 5 1 270 = 2 × 3 × 3 × 3 × 5 = 2 × 33 × 5
200
200 = 2 × 2 × 2 × 5 × 5 = 23 × 52 e
450 2 450 3 225 3 75 5 25 5 5 1 450 = 2 × 3 × 3 × 5 × 5 = 2 × 32 × 52 Chapter 1 | 3
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6. Express the following numbers in the form of prime factorization using factor tree. Express the answers in index notation. .g .
28
a 56
28 4
2
7
4
2
2
28 = 2 × 2 × 7 = 22 × 7
b 252
252 12
2
3
7
300
3
2
315
75 2
91 7
315 9
25 5
300 = 2 × 2 × 3 × 5 × 5 = 22 × 3 × 52
13
364 = 2 × 2 × 7 × 13 = 22 × 7 × 13
e
2
7
364
2
252 = 2 × 2 × 3 × 3 × 7 = 22 × 32 × 7
4
2
4
2
d 300
2
364
21 3
14
56 = 2 × 2 × 2 × 7 = 23 × 7
c
4
56
3 5
35 3
5
7
315 = 3 × 3 × 5 × 7 = 32 × 5 × 7
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Practice 2
Highest common factor (HCF)
1. Determine if each of the following numbers is a common factor for the set of numbers in the brackets. .g .
4 (12 and 32) 12 ÷ 4 = 3 32 ÷ 4 = 8 So, 4 is a common factor for 12 and 32.
b 8 (40, 96 and 116) 40 ÷ 8 = 5 96 ÷ 8 = 12 116 ÷ 8 = 14 R 4 So, 8 is not a common factor for 40, 96 and 116.
a 6 (48 and 59) 48 ÷ 6 = 8 59 ÷ 6 = 9 R 5 So, 6 is not a common factor for 48 and 59.
c
13 (65, 91 and 143) 65 ÷ 13 = 5 91 ÷ 13 = 7 143 ÷ 13 = 11 So, 13 is a common factor for 65, 91 and 143.
2. List the common factors of the sets of numbers. .g .
6 and 30 Factors of 6 = 1, 2, 3, 6 Factors of 30 = 1, 2, 3, 5, 6, 10, 15, 30 So, common factors for 6 and 30 are 1, 2, 3 and 6.
a 52 and 78 Factors of 52 = 1, 2, 4, 13, 26, 52 Factors of 78 = 1, 2, 3, 6, 13, 26, 39, 78 So, common factors for 52 and 78 are 1, 2, 13 and 26.
Chapter 1 | 5
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b 66 and 102 Factors of 66 = 1, 2, 3, 6, 11, 22, 33, 66 Factors of 102 = 1, 2, 3, 6, 17, 34, 51, 102 So, common factors for 66 and 102 are 1, 2, 3 and 6.
c
28, 32 and 40 Factors of 28 = 1, 2, 4, 7, 14, 28 Factors of 32 = 1, 2, 4, 8, 16, 32 Factors of 40 = 1, 2, 4, 5, 8, 10, 20, 40 So, common factors for 28, 32 and 40 are 1, 2 and 4.
d 40, 56 and 88 Factors of 40 = 1, 2, 4, 5, 8, 10, 20, 40 Factors of 56 = 1, 2, 4, 7, 8, 14, 28, 56 Factors of 88 = 1, 2, 4, 8, 11, 22, 44, 88 So, common factors for 40, 56 and 88 are 1, 2, 4 and 8.
3. Circle the common factors of the numbers. .g .
66 and 120
2
4
3
6
a 20 and 80
5
4
10
7
b 38 and 80
4
3
8
2
c
20, 70 and 120
5
2
20
10
d 32, 96 and 140
2
3
4
8
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4. Find the highest common factor (HCF) for each set of numbers. Use the repeated short division method. .g .
a 40 and 56
12 and 28 2 12 2 6 3
28 14 7
2 40 2 20 2 10 5
HCF of 12 and 28 = 2 × 2 =4
b 42 and 66 2 42 3 21 7
HCF of 40 and 56 = 2 × 2 × 2 =8
c 66 33 11
2 20 5 10 2
40 20 4
HCF of 20, 40 and 70 = 2 × 5 = 10
36 12 4 2
90 30 10 5
HCF of 18, 36 and 90 = 3 × 3 × 2 = 18
e 70 35 7
18, 36 and 90 3 18 3 6 2 2 1
HCF of 42 and 66 = 2 × 3 =6
d 20, 40 and 70
56 28 14 7
48, 60 and 102 2 48 3 24 8
60 30 10
102 51 17
HCF of 48, 60 and 102 = 2 × 3 =6
Chapter 1 | 7
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