In mathematics, a rational number is a number such as −3/7 that can be expressed as the quotient or fraction p/q of two integers, a numerator p and a non-zero denominator q.[1] Every integer is a rational number: for example, 5 = 5/1. The set of all rational numbers, also referred to as "the rationals",[2] the field of rationals[3] or the field of rational numbers is usually denoted by a boldface Q (or blackboard bold {\displaystyle \mathbb {Q} }\mathbb {Q} , Unicode 𝐐/ℚ);[4][5] it was thus denoted in 1895 by Giuseppe Peano after quoziente, Italian for "quotient".⁶