\begin{definition}[Definition:Set of Residue Classes/Least Positive]
Let $\eqclass a m$ be the residue class of $a$ (modulo $m$).
Let $r$ be the smallest non-negative integer in $\eqclass a m$.
Then from Integer is Congruent to Integer less than Modulus:
:$0 \le r < m$
and:
:$a \equiv r \pmod m$
Then $r$ is called the '''least positive residue''' of $a \pmod m$.
\end{definition}