I tried to get into Spivak's Calculus only to find that I've never been taught the type of Math presented there.
First chapters talk about the properties of numbers, then mathematical induction, assertions, etc. In other words, things I've never heard of.
While I did take some calculus courses related to derivates, integrals and differential equations, most of it was very methodical as in ''use this equation to get the answer''.
How does one transition from simple math to the more rigorous and complicate type of math presented in these type of books?