Multiplication: Finding Four Times a Number

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.

Answer

Twice 5 is 10, so A is 10.

Double 10 is 20, so B is 20.

So 4 × 5 is 20.