Answer
Rational numbers are numbers that can be expressed as a quotient (or ratio) of two integers, $q$ and $n$, $\frac{q}{n}$, where $n\ne0$.
Irrational numbers are numbers that cannot be expressed as a quotient (or ratio) of two integers.
Work Step by Step
Rational numbers are numbers that can be expressed as a quotient (or ratio) of two integers $q$ and $n$, $\frac{q}{n}$, where $n\ne0$.
Irrational numbers are numbers that cannot be expressed as a quotient (or ratio) of two integers.
In other words, to determine if a number is irrational, we first see if it is rational. If a real number is not a rational number, then we know that it must be an irrational number.