Wednesday, July 20, 2005

Great Math Trick

I just learned a quick and easy way to multiply any two numbers from 11-19 in your head in seconds. Here's how:
  1. Say you want to add 15 x 13. Put the biggest number on top (with your mind's eye).
  2. Draw the shape of Africa around the 1-5 on the top and the 3 on the bottom.
  3. Add these two numbers and add a zero (now we have 15+3=18, add 0= 180
  4. Now mulitply the digit on the bottom right (3) and the top right (5) and you get 15.
  5. Add the two numbers you now have (180 + 15) and you have the final answer (195).
With a little practice, you can do everything from 11x11 to 19x19 - all inside your noggin.

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