Square root

A square root is the number that you multiply twice to get another number. You know, like √2. Square roots are basically squares in reverse.

History
It goes back as far as the history of mathematics. You know how 2×2=4, and 9+10=21? That's square roots in disguise!

Examples

 * √16 is √2 to the fourth power, making it times better. In this case, √16 = 4!
 * √10 is objectively the best because there are so many interesting things about it. √10 is close to the mathematical constant $\pi$, which means that it's bound to be approximated as such (in fact, Indian mathematicians thought that it equaled π. Remember Protegent?).

Crazy or rational?
Well, any whole number that multiplies with itself and transforms into another whole number is a rational square root. Any other number is crazy. Put it in a mental hospital!

Square roots of negative numbers
Square roots of negative numbers don't exist. They must be a figment of your imagination.