Monday, 25 July 2011

Brain Exercise Through Mental Maths - Special Combination 1

Some combinations of numbers are extremely easy to do.  For example, if someone asks you what is 63 x 67, you can say 4221 immediately.  Or  you can solve 32 x 38 instantaneously, which is 1216.

If you look at the two examples above, you will notice that the special combination goes like this: 1) the left hand digits for the numbers to be multiplied are the same, and 2) the right hand digits add up to 10.

And the answer is simply obtained by multiplying the left hand digit with (itself + 1) which gives you the left hand digits of the answer, and multiplying the two right hand digits which gives you the right hand digits of the answer.

Try it with the examples above, or any of the 45 possible special combinations.

You will simply be amazed.

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