noun
rational number
Mathematical term for a number that can be expressed as a fraction of two integers.
有理数は整数の比で表せる数です。
A rational number is a number that can be expressed as a ratio of integers.
0.5は有理数です。
0.5 is a rational number.
整数 is an integer, a subset of rational numbers.
From 有理 (yūri, 'rational') + 数 (sū, 'number'). The term is a direct translation of the Western mathematical concept.