Ask HN: good math books

Dear HN, I need some insight from you.

While I have very solid foundation when it comes to algorithms, unfortunately my math skills are kind of rusty and lacking. I have big holes in my math education, partly because of bad luck with teachers in high-school/college. And the math I learned, I'm starting to forget because of lack of practice.

My domains of interest are data-mining, NLP and AI. These are domains where knowledge of mathematics is required to understand the underlying phenomenons. I mean, I got to some level of knowledge, but it is based on experimentation, empiric conclusions and cargo-culting.

Going to a local college for lectures is not an option.

I want some recommendations on good math books on: calculus, discrete math, probabilities, statistics

I'd also like to start from a comfortable level, so I prefer books that at least start with an introduction of the prerequisites.