Reddit reviews Mathematics: A Discrete Introduction

The best way to learn math is to read math text books.

I think this book prepared me well to explore math on my own:

http://www.amazon.com/gp/offer-listing/0534356389/ref=lp_g_1/103-3484664-0761418

Of course, it won't teach you any vector calculus. It's expensive, but supposedly, you can buy it used for 10 cents. (!?)

Mathematics: A Discrete Introduction is really good. Very clear, good progression, assumes nothing, and has very good problem sets. Note that there is a new edition, but you can still order used copies of the older edition (the one I'm familiar with) very inexpensively.

You can easily simplify the URL - it works just as well.