The letter ‘Q’ is used to represent rational numbers because it comes from the word ‘quotient’. A rational number is defined as any number that can be expressed in the form of a fraction, where the numerator and the denominator are integers, and the denominator is not zero.
Since rational numbers can be interpreted as the quotient of two integers, the designation of ‘Q’ serves as a concise symbolic representation of this concept. In mathematical literature, we often see rational numbers denoted as Q = { p/q | p, q ∈ Z, q ≠ 0 }, which further emphasizes the relationship between rational numbers and their fractional representation.
Overall, the choice of ‘Q’ helps to quickly identify and categorize numbers that share this specific property of being expressible as a ratio, making it easier for scholars and students alike to discuss and work with them in various mathematical contexts.