Friday 30 November 2012


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?

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