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Using number lines in Addition and Subtraction

Using number lines in Addition and Subtraction. By Amani El-Alawneh. Adding numbers using the number line. 25. 47. So how do we do this using the number line?. We use the strategy called: Counting Up. You need to think about: What number shall I start with on my number line?

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Using number lines in Addition and Subtraction

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  1. Using number lines in Addition andSubtraction By Amani El-Alawneh

  2. Adding numbers using the number line. 25 47 So how do we do this using the number line?

  3. We use the strategy called:Counting 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?

  4. Use the counting up method!! +20 25 + 47 = +3 +2 47 67 70 72 So we start at the biggest number…47 Andcount up 25 places What number do we end on??? So…. 25 + 47 = 72

  5. 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?

  6. + 34 = 57 +10 +10 +3 34 44 54 57 34 57 So what is 10 + 10 + 3 = 23 So….. + 34 = 57 23

  7. Can I use the counting up strategy for Subtraction too? YES Have a look at this question! 43 – 27 = 16 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

  9. Have a go at these questions now using number lines and the counting on strategy: • 55 + 18 = • 29 + 40 = • 33 + = 51 • + 14 = 35 • 22 + 15 = • 45 – 25 = • 54 – 26 = • – 19 =36 • 28 – = 14 • 43 – 37 = Extra for Experts: • 154 – 147 • 172 – 133 • 198 – 188 • 134 – 119 • 176 - 134 • 123 + 19 • 199 + 98 • 147 + 76 • 201 + 97 • 185 + 89

  10. Work out the following calculations mentally: • 43 – 37 • 102 – 98 • 154 – 147 • 3005 – 2997

  11. How can we show this using the number line: 43 – 37 3 + 3 = 6 +3 +3 So, 43 – 37 = 6 37 40 43 154 – 147 +4 3 + 4 = 7 +3 So, 154 – 147= 7 147 150 154

  12. 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??

  13. - 285 = 39 + + 300 285

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