Residues Modulo

The list of all possible remainders when dividing an integer by $n$. Also known as a “least nonnegative residue modulo”

Example:

Residues modulo 5 are:
$\{0,1,2,3,4\}$

When you divide 5 by 5, the remainder is 0.
When you divide 6 (or 1) by 5, the remainder is 1.
When you divide 7 (or 2) by 5, the remainder is 2.
When you divide 8 (or 3) by 5, the remainder is 3.
When you divide 9 (or 4) by 5, the remainder is 4.