Why is 1 greater than 0? Using Math to Prove the Obvious (blog.nathanhleung.com)

Supposing I am going to be teaching an AGI, I would start with set theory and base natural numbers on the cardinality of sets.

https://en.wikipedia.org/wiki/Set-theoretic_definition_of_na...

The AGI would have the built-in ability to count the elements of a set that grounds this behavior.

If you're studying math, that's what you usually do in the first year: constructing and proving the obvious via axioms. It's an exhausting and tedious exercise, spread across different topics like analysis, linear algebra, probability theory, and separates the wheat from the chaff. After that, you are prepared for the interesting and non-obvious math topics.