[bushi_do]

The thing about math(s) is that it's cumulative--it builds on all the previous math(s) you learned or should have learned.

I would literally go back as far as necessary (2nd grade/form even) until you find math that isn't challenging, but still takes mental effort to remember. For example, do you remember fractions? exponents? If not completely, go back and re-learn them.

Then progress grade by grade will go much much quicker than the first time you learned them. Khan Academy is a good help.

Someone else mentioned drills and Schaum's. I second that. Drilling is even more necessary as one gets older (I say this as an oldster.)

Once you've exhausted grade-school math, you would be ready for some of the other suggestions listed by others.

[mindcrime]

I literally went all the way back to "pre algebra" when I started down this path. It bruises the ego a little bit, but as you say, it goes faster the nth time around. And it really is important to have the prereq stuff down, or you'll start flailing with the later material, not because it's conceptually difficult, but because of not remembering how to do the "easy" stuff.

In one of his videos Professor Leonard says "Calculus is the class you take to finally fail Algebra". I think there is some merit to that.

[noneeeed]

Yeah, I'm definitely up for doing that. I don't need to go back to fractions, but I think I'd like to start from the beginning of basic algebra. I figure that even if I know the material, the practice will help before I move on.