Start here: http://en.wikipedia.org/wiki/Set_theory#Basic_concepts

You can just attend calculus 101 when the next semester opens, in any university.

You mean audit a class? Not sure why you got downmodded, as far as I know you most universities allow people to audit as much as they want.

Edit: Never mind, you go the downmod for saying calc 101 - it's certainly not a 101 class.

Not 101 (technically it was labeled 161), but at the Univ. of Chicago (where I went), Spivak was the first Calc class on the honors track--i.e. the honors variant of 101. And that course did exactly what he's talking about.

In the two universities I attended, the Technion and HUJI, it was as I described. In fact, I did not know there existed such a thing as a first-year calculus course that doesn't include defining "number" and "addition" from the ground up.

So maybe not just any university, sorry.

They didn't do that in my calc 101 class. Maybe at Princeton or something.