High school student, currently trying to self study further mathematics.

Topics I'm studying include discrete mathematics (propositional logic and set theory in particular), proof methods and calculus.

...and for anyone curious, here's a list of books I'm using!

1. Mathematical Proofs, A Transition to Advanced Mathematics (4th Edition)

2. Calculus Volume 1

Mathematical Proofs can be downloaded online in PDF form, and Calculus Volume 1 can be found on OpenStax. I suggest both, as they've been the most helpful out of the ones I've looked at so far.