Multiply Up to 20 X 20 In Your Head

Lets try 15 x 13.

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

2. Then draw the shape of Africa mentally so it covers the 15 and the 3 from the 13 below. Those covered numbers are all you need.

3. Now add 15 + 3 = 18

4. Add a zero behind it (i.e., multiply by 10) to get 180.

5. Multiply the covered lower 3 by the single digit above it, in this case the "5" (3 x 5 = 15)

6. Add the products from steps 5 and 6 to get your answer. 180 + 15 = 195.

That's it! Wasn't that easy? Practice it on paper first!