User:Sandeepr1987/sandbox

Shortcut for finding cube of a two digit Number (BY SANDEEP.R, RANCHI):

First we need to memorize the cubes of numbers from 1 to 9.

13=1

23=8

33=27

43=64

53=125

63=216

73=343

83=512

93=729

Consider a two digit number in the form of ab eg. 79.

Now to find (ab)3 = (79)3

The formula is what we have learnt in Schools. i.e

=>(a+b)3 = a3 + 3ab(a+b) + b3

=>(a+b)3 = a3 + 3a2b + 3b2a + b3

Now in our case:

(ab)3 = a3 + 3a2b + 3b2a + b3

Solution for (32)3.