Maths tricks

[TheURL]

This guy is a real nerd but it's very clever - especially the algebraic explanation at the end!

 

[Retro]

Incredible. He could square those numbers fast enough to have an instant - and correct - answer the moment the number had been given to him.

For even more mind bending maths, check out Numberphile.

https://youtube.com/user/numberphile