[11001]

Textbooks and exercises. Avoid shortcuts such as online tutorials or anything with "for hackers" in the title.

[egdelwonk]

I've been using Khan Academy to refresh my skills and it's been really helpful, but do you have any recommendations for textbooks?

I'm 10 years out of school and haven't really needed to flex my math muscles in years.

[j2kun]

If you're past calculus, I'd say start with Sheldon Axler's Linear Algebra Done Right (it has the most immediate applications, and linear algebra is essential for almost all higher mathematics).

[11001]

Any particular "math" you're interested in?

If you just want to get your foot in with pure math I'd recommend studying basic abstract algebra and analysis at the same time. For abstract algebra look into Hungerford (Intro, not his grad text), for analysis, maybe Rudin, or Kolmogorov and Smirnov.