In mathematics, a rational number is any number that can be expressed as the quotient or fraction $\frac pq$ of two integers, 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 $\mathbb{Q}$; it was thus named in 1895 by Peano after quoziente, Italian for "quotient".

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