The multiplication table will not occur in this book, not even the theorem,2 \cdot 2 = 4,but I would recommend, as an exercise, that you define2 = 1 + 1,
4 = (((1 + 1) + 1) + 1)and then prove the theorem.

— Edmund Landau Grundlagen der Analysis [Foundations of Analysis (1930)

More quotes by Edmund Landau

Foundations of Analysis (1960)

Grundlagen der Analysis [Foundations of Analysis (1930)

Grundlagen der Analysis [Foundations of Analysis (1930)

Quote text and notes from Wikiquote: Edmund Landau (page history), available under CC BY-SA 4.0. Source quality and labels are our own summary of what Wikiquote records.