Expressions

A rational number is any number that can be written as a fraction $\frac{a}{b}$ where $a$ and $b$ are integers and $b\ne 0$. Every integer is rational because it can be written with a denominator of 1, such as $7=\frac{7}{1}$. When you divide the numerator by the denominator, the decimal either ends (terminating) or repeats a pattern (repeating). If a decimal never ends and never repeats, the number is irrational. Square roots of perfect squares are rational; square roots of non-perfect squares are irrational.