Can I use doubling and halving to solve 2’s, 5’s and 10’s mult/div problems?

- 18 x 5 = Double the 5 and half the 18 so the new times table is 9 x 10=90

- 13 x 5 = You can't do the strategy because you can't half the 13.

- I have 4 cows on my farm. How many legs are there in total? Double the 4 and half the 4 so the new times table is 8 x 2 = 16

- I went to the shop and bought 4 bags of lollies, each bag has 20 lollies. How many lollies do I have altogether? Double the 4 and half the 20 so the new times table is 8 x 10 = 80

- In class 5 people have 40 colouring in pencils each. How many do they have altogether? Double the 5 and half the 40 so the new times table is 20 x 10 = 200

Awesome Ryleigh. Did you move up a workshop?

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