As I know the "1 + 1 = 2" question has been asked before, my question (for now anyway) is more specific: Assuming as little as possible and accepting as few definitions as possible, what are the very basic axioms and definitions that you absolutely must accept in order to prove 1 + 1 = 2?
Whenever this question gets asked, the immediate responses are things like, "well you have to prove what '1', '2', '+', and '=' are." And that's fine, but in order to prove all four of those things, and then ultimately what they mean together, what is the absolute bare minimum that you simply must accept for any approach to this problem with a completely blank slate? e.g. Peano's axioms?