Multiply Up to 20X20 Easily

In just two minutes you should learn to quickly multiply up to 20x20 . 
 With this trick, you will be able to multiply any two numbers from 11 to 19 in your head quickly, without the use of a calculator.

I assume that you know your multiplication table reasonably well up to 10x10.

Try

• Take 15 x 13 for an example.
• Always place the larger number of the two on top in your mind.
• 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.
• First add 15 + 3 = 18
• Add a zero behind it (multiply by 10) to get 180.
• Multiply the covered lower 3 x the single digit above it the "5" (3x5= 15)
• Add 180 + 15 = 195

That is It! Wasn't that easy?