Quick-Mind

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Sunday, June 11, 2006

More Tricks!

Here are some more mental Math for you to try ....

Quick Square - Did you know that there is a quick way of squaring a two digit number which ends in 5? Just multiply the first digit by that number +1 and stick a 25 after your product and there's your answer ...^^
Example:
Q. What is 35 squared?
A. 3x4=12
.....now stick on the 25
.....the answer is 1225

Times Eleven - The eleven times table has always been very easy to learn up to 9 x 11. Here's a way of multiplying large numbers by 11 too:
Example:
Q. What is 324 x 11 ?
A. Write down the first digit... 3
.......Add the first and second digits .. 3 + 2 = 5
.......Add the second and third digits .. 2 + 4 = 6
.......Write down the last digit ........ 4
The answer is 3564

Multiplying by Four - Doubling a number is quite easy. We learn doubles as some of our first number facts. So multiplying by four is easily achieved by doubling, then doubling again.
Example:
Q. What is 742 x 4?
A. 742 x 2 = 1484
.....1484 x 2 = 2968
The answer is 2968

Hope you learn something ^^

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