Who discovered or invented rational numbers?

Rational numbers were not invented by one single person, but their discovery and study trace back to ancient Greek mathematicians, especially the Pythagoreans, who recognized fractions (ratios of integers) as valid numbers. Over centuries, their use was refined by Indian, Islamic, and later European mathematicians.

• The concept of rational numbers comes from the word ratio. Rational numbers are numbers that can be expressed as p/q, where p and q are integers and q ≠ 0.
• Ancient Egyptians and Babylonians already used fractions in trade and astronomy, but it was the Greeks who formally studied them as mathematical objects.
• The Pythagoreans believed that “all quantities can be expressed as whole numbers or their ratios.” They considered fractions (like 1/2, 3/4, etc.) as rational representations of parts of a whole.
• Later, Indian mathematicians (like Aryabhata and Brahmagupta) and Islamic scholars extended the use of rational numbers in algebra and arithmetic.
• In modern mathematics, the set of rational numbers is denoted by Q, from the word quotient.

Also Check: NCERT Solution for Class 8 Rational Number