Trick to find cubes of numbers from 11 to 99.
If a 2-digit number is written in form ‘ab’ then a is tens place
digit and b is unit place digit.
To find its cube find:
1)
a x a x a put 3 zeros(000) after it.
2)
3 x a x a x b; put 2 zeros (00) after it.
3)
3 x a x b x b; put 1 zero after it.
4)
b x b x b
5)
Add all of the above to get the required cube of
the given 2-digit number.
6)
Trick can be used to find cubes of 11 to 99. Of course
10’s cube is 1000.
Ex. To find cube of 13:
1)
1 x 1 x 1 = 1 => 1000
2)
3 x 1 x 1 x 3 = 9 => 900
3)
3 x 1 x 3 x 3 = 3 x 3 x 3 = 9 x 3 = 27 => 270
4)
3 x 3 x 3 = 27
1
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5) 2197
e
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