In this worksheet we use a quick number trick to multiply numbers by four.
Here are five candles.
If we double this number we get 2 × 5 = 10 candles
If we double this number again we get 2 × 10 = 20 candles
This is 4 lots of the original 5 candles so 4 × 5 = 20
To multiply a number by 4, we double it and double the answer again.
Example
Find 4 × 5 by using this table to find first A and then B.
Twice 5 is |
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Double |
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is |
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Then 4 × 5 is |
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Answer
Twice 5 is 10, so A is 10.
Double 10 is 20, so B is 20.
So 4 × 5 is 20.