With then the relation defined as induces an equivalence relation therefore given any we get an equivalence class , and we define to lighten the standard notation of equivalence classes
The Integers Modulo
Suppose that , then we define and call this set the integers modulo
Addition in
Suppose that , then we define
Multiplication in
Suppose that , then we define
choice of representative doesn't matter for addition
Suppose that and that and , then
Consider the set which is defined as , we'd like to show that it is equal to