what does it mean when a number is rational
In mathematics, a rational number is any number that can be expressed as the quotient or fraction p / q of two integers, p and q, with the denominator q not equal to zero. Since q may be equal to 1, every integer is a rational number. The set of all rational numbers is usually denoted by a boldface Q (or blackboard bold, Unicode â); it was thus denoted in 1895 by Peano after quoziente, Italian for  quotient .