Calculating the square of two digit numbers!

Ever wanted to impress your friends by calculating crazy squares in your head? Well here's how!

It's actually really simple~ take, for example, 15*15. The product is obviously 225. Take 15 and split it into ten's and one's, so what you're left with is: tens~10, ones~5.

Now apply this simple formula:

a^2 + 2(a)(b) + b^2 = your product!
where:
a is either the tens or ones, and;
b is either the tens or ones (not the same as a)
** FOR SIMPLICITY I always choose "a" as my tens value.

For our example:

(10)^2 + 2(10)(5) + (5)^2
= 100 + 100 + 25
= 225

Magic!

Take another example: 33x33
tens~30
ones~3

(30)^2 + 2(30)(3) + (3)^2
= 900 + 180 + 9
= 1089

It works!

I created this idea on my own but I'm pretty sure some else has done it before me. This can easily be modified to find the squares of triple digit numbers (adding a "z" component), and it can also be modified to take the multiplication of two numbers rather than the square of one! I'll post how in my next article, stay tuned~