Unit 3 – Addition and subtraction
Doubles and halves
Let’s double and halve some numbers.
1
What is half of 68?
What is double 23?
23 + 23 = 20 + 20 + 3 + 3 = 40 + 6 = 46 So, double 23 is 46.
68 = 60 + 8
= 30 + 30 + 4 + 4 = 34 + 34
So, half of 68 is 34.
1 Use counting blocks to help double these numbers. (a) (b) (c)
2 Use counting blocks to help halve these numbers. (a) (b) (c)
37
9781380050687__text.indb 37
03/05/2022 10:18
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