Fast Subtraction Facts. Memorizing long lists of multiplication tables can be a snore. And flashcards with additions, subtractions, division and so on are not exactly the way to stave off math-induced naps. But the Math Gear series of books will keep elementary school kids wide awake as they learn their math skills, thanks to six fun spreads with two-sided fact wheels. With nothing similar on the market, these self-standing books with a high-tech look allow children to learn their math with the spin of a wheel.