Rational Number

 A rational number is a number that can be expressed as the quotient or fraction of two integers, where the denominator is not zero. In other words, a rational number is a fraction where the numerator and denominator are both integers.

Mathematically, a rational number "q" can be represented as:

q = p / r

Where "p" and "r" are integers, and "r" is not equal to zero.

Rational numbers include integers as a subset, since any integer "n" can be represented as a rational number by setting the denominator to 1 (n = n/1). However, not all rational numbers are integers, as there are many fractions that cannot be simplified to a whole number.

For example:

- 1/2

- 3/4

- -5/6

- 2 (can be represented as 2/1)

On the other hand, numbers like π (pi) and √2 (square root of 2) are not rational because they cannot be expressed as a fraction of two integers. These types of numbers are called irrational numbers.