that is, the set of all equivalence classes in , where the representatives are less than and relatively prime to (including 1)

example,

since 5,7, and 11 are the integers between 1 and 12 that are relatively prime to 12.

is an Abelian group with respect to (you know what means, right?).

so what would look like for some prime ?

can you find the order of the elements? do you remember how order is defined?