In school, I didn't make it much past basic calculus/algebra. As a self-taught programmer (my highest level of education is a high-school diploma), I seriously wish I could go back and put more effort into math. I love looking at these types of topics, but I have absolutely no clue what I'm looking at.

If anyone can recommend any books, courses, or any other material that starts from high-school level math, and gradually increases in complexity, I would love to look at it.

Cheers :)