Saturday, September 12, 2015

Short cut squaring of any two digit number just in few seconds with help of algebraic identity


We can utilize following algebraic identity to easily find square of any two digit number
A2 = (A - d) x (A + d) + d2
Where, d = any assumed value to easily compute square.
Naturally, this formula works for any value of d, but we choose d to be the distance to a number close to A that is easy to multiply. 
For example,
To find square of the number 23,
Let, d = 3, A = 23
So,
A2 = (A - d) x (A + d) + d2
= (23 - 3) x (23 + 3) + (3)2
= 20 x 26 + 9
= 520 + 9
= 529
Another example,
To find square of the number 48,
Let, d = 2, A = 48
So,
A2 = (A - d) x (A + d) + d2
= (48 - 2) x (48 + 2) + (2)2
= 46 x 50 + 4
= 2300 + 4
= 2304

No comments:

Post a Comment