How many element are contain in a set of residues module

A set of residues modulo $n$ (also known as a complete residue system modulo $n$) contains all the distinct remainders when integers are divided by $n$. These remainders are typically represented by the integers from $0$ to $n-1$.

The number of elements in a set of residues modulo $n$ is equal to $n$.

For example, for modulo 5, the set of residues is $\{0, 1, 2, 3, 4\}$, which contains 5 elements.

The number of elements is $\boxed{n}$.