This week someone posted on Facebook about reviewing insanely simple 9th grade math problems and I mentioned I'd been looking for something for review, but couldn't go higher than 5th grade because the material was too difficult.
Yesterday at Volunteers of America for 90 cents I found the neatest book, "Math on Call," Houghton Mifflin, 2004. It's attractive, nicely arranged, color coded with clear explanations that are somewhat below my reading level, even if the math isn't. So I went online to check out the grade level and found it is "sixth to eighth." It includes number theory, computation (which is about all I can do), algebra, graphs and statistics, geometry, ratio/proportion/percent, probability and odds, then study tips, test taking tips, tables, patterns (like Fibonacci) and systems (Roman numerals, Mayan, etc.) This is a terrific "review," and if elementary kids are doing this, God bless'em. Also, the used ones I saw on-line were about $40--I may be bad at math, but that's more than 90 cents.