Definition: In mathematics, the term “rational” refers to a number that can be expressed as the quotient or fraction of two integers, where the denominator is non-zero.


  • A rational number can be written in the form a/b, where a and b are integers, and b is not equal to zero.
  • The numerator (a) represents the dividend, while the denominator (b) represents the divisor.
  • The word “rational” is derived from the Latin word “ratio,” which means “ratio” or “quotient.”
  • All integers are rational numbers since they can be expressed as fractions with a denominator of 1 (e.g., 5 = 5/1).
  • Rational numbers can be either positive, negative, or zero.
  • Rational numbers include fractions, terminating decimals, and repeating decimals.
  • The set of rational numbers is denoted by the symbol ℚ or Q.