# Addition

## arithmetic operation / From Wikipedia, the free encyclopedia

Not to be confused with building extension which are also called *additions*

In mathematics, **addition**, represented by the symbol $+$, is an operation which combines two mathematical objects together into another mathematical object of the same type, called the sum.^{[1]}^{[2]}^{[3]} Addition can occur with simple objects such as numbers, and more complex objects and concepts such as vectors and matrices.^{[4]}

Addition has several important properties. It is commutative, meaning that the order of the operands does not matter, and it is associative, meaning that when one adds more than two numbers, the order in which addition is performed does not matter (see *Summation*). Repeated addition of 1 is the same as counting. Addition of 0 does not change a number. Addition also obeys predictable rules concerning related operations such as subtraction and multiplication.