Commutative ring

In algebra, commutative ring is a set of elements in which you can add and multiply and have multiplication distribute over addition. An example of a commutative ring is the set of integers. If we add two integers, we get an integer and if we multiply two integers we get another integer. Moreover, multiplication distributes in the sense that if "a", "b", and "c" are integers, then "c*(a+b)=ca+cb".