Explanation

The set $left{frac{p}{q} : p, q in mathbb{Z}, q neq 0right}$ represents the set of rational numbers.

Rational Numbers: A number is considered rational if expressed as the quotient $frac{p}{q}$, where $p$ and $q$ are integers and $q\mathrm{\ne }0$

This set includes numbers like $frac{1}{2}$, $-frac{3}{4}$, and $7$ (which can be written as $frac{7}{1}$).