BortimusPrime
Ostrich
For math/science/engineering I'd just grab a used textbook that has some of the answers in the back and work through it. College textbooks become worthless once the edition changes (they just mix up the questions, and then the book is useless when the prof. assigns questions from the book for homework, college being the extractive industry it is...), so you can pick one up for a couple bucks off half.com.
For programming I'd say just look for online tutorials in the language you want to learn, and once you get the basics just try to code projects on your own, using online references when you don't know how to do something.
For programming I'd say just look for online tutorials in the language you want to learn, and once you get the basics just try to code projects on your own, using online references when you don't know how to do something.