Full Idea
The 'rational' numbers are all those that can be represented in the form m/n (i.e. as fractions), where m and n are natural numbers different from zero.
Gist of Idea
The 'rational' numbers are those representable as fractions
Source
Michèle Friend (Introducing the Philosophy of Mathematics [2007], 1.5)
Book Reference
Friend,Michèle: 'Introducing the Philosophy of Mathematics' [Acumen 2007], p.17
A Reaction
Pythagoreans needed numbers to stop there, in order to represent the whole of reality numerically. See irrational numbers for the ensuing disaster. How can a universe with a finite number of particles contain numbers that are not 'rational'?