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

We can utilize following algebraic identity to easily find square of any three digit number

A² = (A - d) x (A + d) + d²

Where, d = any assumed value to easily compute square.

We can quickly square three-digit numbers by rounding up and down to the nearest hundred. 
For example,

To find square of the number 223,

Let, d = 23, A = 223

So,

A² = (A - d) x (A + d) + d²

= (223 - 23) x (223 + 23) + (23)²

= 200 x 246 + 529

= 49200 + 529

             = 49729