Multiply Up to 20X20 In Your Head

This is an strategy to multiply from 11 to 20 in your head easily.

Try this:

1. Take 15 x 13 for an example.

2. Always place the larger number of the two on top in your mind.

3. Then add the bigger number with the last digit of the smaller number. So add 15 + 3 = 18

4. Then multiply it by 10 to get 180.

5. Multiply the covered lower 3 from the 13 by the single digit above it the "5" (3x5= 15)

6. Add 180 + 15 = 195.

This works only with numbers from 11-20.

discovered by Helen