Using number lines in Addition and Subtraction

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Using number lines in Addition andSubtraction
By Amani El-Alawneh
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Adding numbers using the number line.
47
25
So how do we do this using the number line?
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We use the strategy calledCounting Up
You need to think about What number shall I
start with on my number line? What number do we
want to count up by? Are there any number bonds
that can help me?
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• 25 47

Use the counting up method!!
20
3
2
47
67
70
72
So we start at the biggest number47
And count up 25 places
What number do we end on???
So. 25 47
72
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Use the Counting Up Strategy
34 57
?
Remember -You need to think about What number
shall I start with on my number line? What number
do we want to count up by? Are there any number
bonds that can help me?
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34 57
10
10
3
34
44
54
57
34
57
So what is
10 10 3 23 So.. 34 57
23
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Can I use the counting up strategy for
Subtraction too?
YES

• Have a look at this question!
• 43 27

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What number shall I start from on my number line?
What number do I want to get to?
What number shall count on by?
Can any number bond make counting on easier for
me?
10 3 3 16
10
3
3
27
37
40
43
8
32 - 18
What number shall I start from on my number line?
What number do I want to get to?
What number shall count on by?
Can any number bond make counting on easier for
me?
10
2
2
18
20
30
32
2 10 2 14 So.
32 - 18
14
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Have a go at these questions now using number
lines and the counting on strategy

1. 45 25
2. 54 26
3. 19 36
4. 28 14
5. 43 37

1. 55 18
2. 29 40
3. 33 51
4. 14 35
5. 22 15

Extra for Experts

1. 154 147
2. 172 133
3. 198 188
4. 134 119
5. 176 - 134

1. 123 19
2. 199 98
3. 147 76
4. 201 97
5. 185 89

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Work out the following calculations mentally

• 43 37
• 102 98
• 154 147
• 3005 2997

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How can we show this using the number line
43 37
3 3 6
3
3
So, 43 37 6
40
37
43
154 147
4
3 4 7
3
So, 154 147 7
147
150
154
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Have a look at these Calculations
What is it about the numbers that made you
decide to use mental method or a number line?

• 144 138
• 89 34
• 134 123
• 125 - 76

Do you always need to use a number line when the
numbers are a long way apart??
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- 285 39


285
300