Quadratic Residue/Examples/5

Example of Quadratic Residues
The set of quadratic residues modulo $5$ is:
 * $\set {1, 4}$

Proof
To list the quadratic residues of $5$ it is enough to work out the squares $1^2, 2^2, 3^2, 4^2$ modulo $5$.

So the set of quadratic residues modulo $5$ is:
 * $\set {1, 4}$

The set of quadratic non-residues of $5$ therefore consists of all the other non-zero least positive residues:
 * $\set {2, 3}$