I actually use algebra most often of all the mathematics I have learned, with simple stats right after that. A couple of years back, I decided I wanted to brush up on my algebra, so I picked up Forgotten Algebra by Barbara Lee Bleau. It is a quick, breezy book that takes you through everything you really need to know. I found it kind of fun (sick I know).
I worked through all the problems and examples, and I felt pretty good about it all. I jotted down some quick notes, which tonight I decided to typeset in LaTeX and post here. I needed a refresher on LaTeX too.