[CrayZee]

To cover your bases for econ, engineering, and the sciences, you usually need the first year of calculus (i.e., differential, integral, infinite sequences and series and such). If you can learn those good, you'll be fine with the maths.

For review, maybe Schaum's Outline texts are a good organized way to study since they have both solutions to example problems and all of the answers in the back to homework-type problems.

I also recommend going to the university/college bookstores if local, or possibly online, that you might attend to see what texts they hawk. If you're a really good self-study, you can write down the titles, authors, and/or ISBNs for cheaper online purchase ahead of time (the editions may change by the time you take the courses however).