Tuesday, March 6, 2012

Tips and Tricks: Multiplication


The multiplication table of 1 is a no-brainer, BUT, let's face it! even adults sometimes are having a hard time doing numbers in their heads!

I can mentally calculate tables 2 to 5, and table of 10 is as no-braner as the multiplication of 1. :D
Then comes, 6, 7, 8 and 9.

You might already knew this, and forgotten about is, so this will help you refresh a Math skill!
  • The Multiplication by Hands - applicable for 6, 7, 8, 9 and 10 as multiplier and multiplicand
    • Step 1 - look at your hands, your thumbs represents number 10, the index finger as 9 and so on, hence, your pinky is number 6.
    • Step 2 - let's set an example. So lets say its 7 x 8. (No calculators pls! that's cheating!) What you do is connect the fingers representing 7 and 8.
    • From the connecting fingers, count each fingers downwards by ten. So thats 10, 20, 30, 40, 50.
    • Step 3 - Count the remaining left fingers and add it to the sum of the remaining right fingers. so that's 3 x 2 = 6
      • Step 4 - Add the sum of step 5 and 6, so that will give you 50 + 6 = 56. Awesom I    know! :D
Take a look:
Photo Courtesy of helpingwithmath.com
I first observed that the digits of the answers if added will always be 9.
And aside from tables 1 and 10, 9 is a no-brainer too! you just have to know the trick!

Example: 9x7. Instead of counting 9 + 9 + 9 + 9 + 9 + 9 + 9... All you need to do is add zero to the digit you are multiplying to 9, in this case 7 will become 70. Then we have to minus that digit to the new set of number, 70 - 7 = 63.

In short: 8 x 9 = 80 - 8 = 72.

Get it, got it!

Do you have more math tricks to share? Comment down below, its time to share yours! Click like for more math tricks! :P

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