More multiplication
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1 Now we know how to multiply by 20 we can use a strategy to multiply by 21. There are 3 rows of 20.
3 × 20 = 60 Now I have 3 rows of 21.
There are 3 more. 3 × 20 = 60 3 × 21 = 63 + 3
I can use this strategy to work out 16 × 19 as well. I just take away 16 from 320.
2 Let’s use this strategy to work out 16 × 21. 16 × 20 = 320 16 × 21 = ? The answer will be 16 more than 16 × 20. + 16
320 + 16 = 336 16 × 21 = 336
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01/12/2021 14:51
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