I don't think there is any book I've read as an adult that was particularly special. If I wasn't already good at math, I wouldn't be reading these books in the

I don't think there is any book I've read as an adult that was particularly special. If I wasn't already good at math, I wouldn't be reading these books in the first place. Not that there weren't good and helpful books, but I wouldn't say any of them were revolutionary to me. But I'd like to mention two books I read as a child which had a life-altering effect. They probably wouldn't do any good for an adult, but might really help your kids... Unfortunately, I don't remember the specific titles or authors (I was probably around 10 yrs old). The first was similar to this book: "Speed Math for Kids: The Fast, Fun Way To Do Basic Calculations." This gave all sorts of advice and tips to quickly do math in your head... simple things, mostly. For example, to multiply by 18 just double, multiply by 10, and subtract 10%; or how it's frequently faster to multiply numbers by moving from most significant digits to least, which is opposite of how we're taught; or how to quickly estimate square roots. This really didn't teach new concepts, but by making routine and tiresome math operations faster and easier, it made the entire field more enjoyable to engage with. The second book was a guide to slide rulers, and I couldn't even find a similar book on Amazon. But learning advanced slide ruler techniques can trigger an epiphany; you learn mathematical relationships, how you can transform how numbers are represented. It was the first time I really saw an elegant structure behind the math.