Full Idea
A number is the index of an operation.
Gist of Idea
A number is a repeated operation
Source
Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 6.021)
Book Reference
Wittgenstein,Ludwig: 'Tractatus Logico-Philosophicus (Pears)', ed/tr. Pears,D. /McGuinness,B. [RKP 1961], p.59
A Reaction
Roughly, this means that a number indicates how many times some basic operation has been performed. Bostock 2009:286 expounds the idea.