Page "Informal mathematics" Paragraph 1

Informal mathematics means any informal mathematical practices, as used in everyday life, or by aboriginal or ancient peoples, without historical or geographical limitation.

Modern mathematics, exceptionally from that point of view, emphasizes formal and strict proofs of all statements from given axioms.

This can usefully be called therefore formal mathematics.

Informal practices are usually understood intuitively and justified with examples — there are no axioms.

This is of direct interest in anthropology and psychology: it casts light on the perceptions and agreements of other cultures.

It is also of interest in developmental psychology as it reflects a naïve understanding of the relationships between numbers and things.

Another term used for informal mathematics is folk mathematics, which is ambiguous ; the mathematical folklore article is dedicated to the usage of that term among professional mathematicians.