Rational number

A "rational" number is a quotient of the form ${\frac {a}{b}}$ where a, b are integers and b ≠ 0. The set of rational numbers, usually denoted by $\mathbb {Q}$ is an example of a totally disconnected set that is not locally compact. The rational numbers are countable. Rational numbers can be identified by their fractional form, or a terminating or repeating decimal.