#MOC # Number Theory Number theory is a branch of mathematics that studies integers and their properties. It can be thought of as the study of the number system. ## Misc Concepts - [[Factorial]] - [[Absolute Value]] ## Number Classifications - [[Rational Numbers]] - [[Integer Numbers]] - [[Coprime Integers]] - [[Complex Numbers]] ## Tricks - [[The Gauss Trick]] - [[The Trick for Quickly Calculating the Sum of First N Odd Integers]] - [[The Trick for Quickly Calculating the Sum of First N Even Integers]] - [[Divisibility Rules]] - [Trick for simple squaring of any two or three digit number](https://www.youtube.com/watch?v=HWF1y5FfGXo) - [Easier multiplication](https://www.youtube.com/watch?v=LgJ5bNHBbD4)