# Rational Numbers Rational numbers are all numbers that can be expressed as a fraction in the form $\frac pq$ where p and q are [[Coprime Integers]]. The symbol for rational numbers is $\mathbb{Q}$. An interesting property of the above (that is used to prove that the [[Square Root of 2 Is Irrational]]) is that either both p and q are odd, or that at most one of them is. If both were even, that would mean that the fraction can be simplified further.