Thursday, October 30, 2008

Simplest way to square a Number

Suppose you want to Square a Number “AB i.e equal to AB^2 = AB * AB

Simplest method to follow is Cris cross mothos: A^2/2AB/B^2
Example 1) Suppose you want to square 24, i.e 24 x 24, so from the criss-cross method.
= 2^2 / 2 (4 x 2) / 4^2
= 4 / 16 / 16 (add carry 1 to 16)

= 4/16+1/6

=4/17/6(add carry to 4)

=4+1/7/6

=576

Example 2) Square of 29 = ?
Now a = 2 and b = 9, by the above observation we substitute the values.
= 2^2 / 2 (2 x 9) / 9^2
= 4 / 36 / 81 ( hear 8 is a carry, so add it to the preceding number )
= 4 / 36 + 8 / 1 ( after adding 8 to 36 you get 44, carry 4 to the preceding number)
= 4 / 44 / 1
= 4 + 4 / 4 / 1
= 8 / 4 / 1
= 841

2 comments:

Ananth said...

useful method, thanks.

Saleem said...

Thank you.
To square a number ending with 5.
eg: 15
multiplication of the first didgit and next no of it. and 25 (i.e 5^2)

Square of 15 is: 1*2 25=2 25 =225
eg: 35 => 3*4 25 => 12 25=> 1225
Eg: 95=> 9*10 25 => 90 25=> 9025
some times the usual methos is more better than the shortcuts.