Speed Maths 3

Yet another method to find Squares faster.
I will start with an example.
Say We need to find the square of 16.
The nearest 10 is 20.
To get 20, we add 4 to 16,
i.e 16+4=20
Since we have added 4, to get the nearest ten.
We subtract 4 from 16..
16-4=12
To get the square of 16, 20 * 12 + (4 ^ 2)
=240 + 16 = 256.
For a 2 digit number we go for the nearest 10.
If it is a 3 digit number we should go for the nearest 100.

Few more examples
1) 24
Nearest 10 is 20.
24- 4=20
So to get the square, 20 * 28 + (4 ^ 2 )
The answer is 576.

2) 111
Nearest 100 is 100
111-11 = 100
So to get the square 100 * 122 + (11^ 2)
=12200+121
=12321

Will post the next one on progressions.
But new concepts in progressions are limited.
So that will be a small post .