A rational number is a type of real number that can be expressed as the ratio or fraction of two integers, where the denominator is not equal to zero. In other words, a rational number is any number that can be written in the form of p/q, where p and q are integers and q is not equal to zero. Examples of rational numbers include 1/3, 2/4, 1/5, 9/3, and so on. Every whole number is a rational number because every whole number can be expressed as a fraction. The set of rational numbers includes all the integers, each of which can be written as a quotient with the integer as the numerator and 1 as the denominator. Rational numbers can be positive, negative, or zero. The opposite of a rational number is also a rational number. Rational numbers can be represented as terminating decimals or repeating decimals.