Full Idea
Every statement of the result of an arithmetical operation is a statement of one of the modes of formation of a given number.
Gist of Idea
Arithmetical results give a mode of formation of a given number
Source
John Stuart Mill (System of Logic [1843], 3.24.5)
Book Reference
Mill,John Stuart: 'System of Logic (9th ed, 2 vols)' [Longmans, Green etc 1875], p.151
A Reaction
Although Mill sticks cautiously to very simple arithmetic, inviting empirical accounts of much higher mathematics, I think the phrase 'modes of formation' of numbers is very helpful. It could take us either into structuralism, or into constructivism.