Solution
= Solution
<Gauss's lemma (number theory)> for <quadratic residues> states: if $p\nmid a$ and $m$ is the number of least positive <residue classes> among $a,2a,\ldots,((p-1)/2)a$ that exceed $p/2$, then $\boxed{(a/p)=(-1)^m}$.
= Solution
<Gauss's lemma (number theory)> for <quadratic residues> states: if $p\nmid a$ and $m$ is the number of least positive <residue classes> among $a,2a,\ldots,((p-1)/2)a$ that exceed $p/2$, then $\boxed{(a/p)=(-1)^m}$.