Precalculus Mathematics in a Nutshell

Precalculus Mathematics in a Nutshell by George Finlay Simmons is one I go back to from time to time to make sure I have mastery of basic math. Someone gave it to me in high school. It’s a tiny book but powerful. It helped me a prepare for college. There’s something very inspiring about understanding geometry, trig, and algebra well enough that you can flip through a few pages, follow along, and basically cover the whole of those subjects as taught in high schools. I later used it to study for the GMAT and GRE and got a 99 percentile math score both times. I’m reasonably intelligent but not a math whiz. The book definitely helped. It is brief but densely-packed with everything you really need to know.