A rational number is one that can be expressed in terms of a ratio.
It can be expressed as a fraction in which the numerator (top number) and denominator (bottom number) are whole numbers, and the denominator is not equal to zero.
In other words, any number that can be represented or written in the p/q form, where 'p' and 'q' are integers and q is a non-zero number, is a rational number.