Contents Chapter 1
Numbers 0 to 10................................................... 1 1 Numbers 0 to 10............................................................................... 2 2 Counting forward and backward..................................................... 4 3 Ordering the numbers...................................................................... 5 4 Comparing numbers........................................................................ 6
Chapter 2
Addition within 9................................................. 12 1 Meaning of addition..........................................................................13 2 Adding numbers............................................................................. 14 3 Adding 0.......................................................................................... 17 4 More about addition........................................................................ 18
Chapter 3
Subtraction within 9..............................................24 1 Meaning of subtraction.................................................................. 25 2 Subtraction of numbers................................................................. 26 3 Counting and subtracting.............................................................. 29 4 Subtraction with 0.......................................................................... 34 5 Subtraction and addition............................................................... 35
Chapter 4
Numbers up to 20.............................................. 39 1 Numbers 11 to 20........................................................................... 40 2 Tens and ones................................................................................ 41 3 Using the signs, = and â&#x2030; ............................................................... 43 4 Using the signs, > and <............................................................... 44 5 Ordering the numbers 11 to 20...................................................... 45
Chapter 5
Addition and Subtraction within 20............................52 1 Adding numbers............................................................................ 53 2 Adding up three 1-digit numbers.................................................. 57 3 Subtracting numbers..................................................................... 59
Chapter 6
Length.............................................................66 1 Words related to length................................................................. 67 2 Comparing and measuring lengths.............................................. 70 iii
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Chapter 7
Mass.............................................................. 76 1 Words related to mass.................................................................. 77 2 Comparing and measuring masses.............................................. 78
Chapter 8
Volume............................................................84 1 Words related to volume............................................................... 85 2 Comparing and measuring volumes............................................ 87
Chapter 9
Numbers up to 100.............................................. 92 1 Numbers from 21 to 100................................................................ 93 2 Digits............................................................................................... 94 3 Place values................................................................................... 95 4 Comparing numbers..................................................................... 96 5 Using the signs, =, â&#x2030; , > and <....................................................... 98 6 Ordering numbers........................................................................ 100 7 Counting forward and backward................................................. 101 8 Counting by twos.......................................................................... 102 9 Counting by fives.......................................................................... 103 10 Counting by tens........................................................................... 104 11 Naming positions.......................................................................... 106
Chapter 10
Addition and Subtraction within 100.......................... 111 1 Adding up two numbers............................................................... 112 2 Using addition to solve problems.................................................. 114 3 Subtracting.................................................................................... 116 4 Subtracting three 1-digit numbers................................................. 117 5 Using subtraction to solve problems............................................ 118
Chapter 11
Combined Operations.......................................... 121 1 Doing combined operations......................................................... 122
Chapter 12
Time.............................................................. 127 1 Times of the day........................................................................... 128 2 Days of the week.......................................................................... 129
Chapter 13
Two-Dimensional (2-D) Shapes............................... 133 1 Names of 2-D shapes................................................................... 134 2 Describing 2-D shapes................................................................. 136 3 Patterns......................................................................................... 137 iv
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Ch a p r te
3
Subtraction within 9
How many pieces of pizza are left?
mes Learning Outco In this chapter students learn to
â&#x20AC;˘ subtract cardinal numbers not exceeding 9, and 0, as well as be aware of validity of the answers
â&#x20AC;˘ analyse and find answers to problems of cardinal numbers not exceeding 9, and 0, as well as be aware of validity of the answers
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Subtraction within 9
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1 Meaning of subtraction
4 minus 1 equals 3.
5 minus 1 is equal to 4.
8 minus 1 is 7.
Minus means take away. Subtraction within 9 CHAPTER
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2 Subtraction of numbers There are four on the leaves. One
jumps into
the water. Three
are left on the leaves now.
4 1
We write :
3
4 – 1 = 3
We read : Four minus one equals three . This is the ‘minus’ sign.
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3
This is the ‘equal’ sign.
Subtraction within 9
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You can also find the answer by : Using your fingers Two children get off the train.
There are five children on the train.
Three children are left on the train.
5 â&#x20AC;&#x201C; 2 = 3 Using cancellation
Using marbles
Using a line number 0 1 2 3 4 5 6 7 8 9 28
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3 Counting and subtracting The rabbit hops down 3 steps. How many more steps does it have to hop down to reach the ground?
2
1
3
4
5
6
7
9
8
9
9–3= 6
3
6
8 – 5 = 3
8 5
0 1 2 3 4 5 6 7 8 9
7 – 2 =
7 2
0 1 2 3 4 5 6 7 8 9 Subtraction within 9 CHAPTER
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He gives 5 peanuts to a monkey.
Suwat has a packet of peanuts.
Then, there are 3 peanuts left in the packet. How many peanuts are there in the packet in the beginning?
–5=3
3
5
Let us fill in the blanks.
– 4 = 3 6–
= 4
8–
= 2 – 2 = 7
Subtraction within 9 CHAPTER
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–1=5 8– 3
=1
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Let us solve some problems.
There are 6 cups on a table. 2 of the cups fall and break. How many cups are left on the table now?
6–2= 4 Answer :
cups are left on the table now.
Kan has 9 crayons. He uses up 7 of them. How many crayons are left with Kan now?
9–7= Answer :
crayons are left with Kan now.
Sanit has 8 goats. He sells off 3 of them. How many goats are left with Sanit now?
Answer :
goats are left with Sanit now .
Keywords
difference 36
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minus
Mathematics Pratomsuksa 1 CHAPTER
subtract 3
subtraction
Subtraction within 9
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A Count and subtract. 1. –
=
–
=
–
=
–
=
2.
3.
4.
B Fill in the blanks correctly. 1. 5 – 1 =
2. 4 – 4 =
3. 9 – 2 =
4. 7 – 1 =
5. 8 – 5 =
6. 7 – 3 =
7. 6 – 4 =
8. 9 – 6 = Subtraction within 9 CHAPTER
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