The Number Devil: A Mathematical Adventure, by Hans Magnus Enzensberger
I brought this home from the thrift store, without any particularly high hopes for getting Dollygirl interested in a story that was supposed to be a mathematical version of The Phantom Tollbooth or Alice in Wonderland. Such books often have a didactic smell of the nursery, even when they're new; and this one is fairly new: it was published in German in 1999, and the English translation came out in 2000. And translated books...well, sometimes they work and sometimes they don't.
If you're old enough, you might remember the Life cereal commercials: let Mikey try it, he hates everything. I am very happy to say that The Number Devil (at least the ten of twelve chapters we've read) has surpassed not only my expectations, but Dollygirl's.
Amazon and elsewhere. Briefly, a math-hating boy named Robert has a series of dreams, each featuring a little red guy with horns who does amazing things with numbers. Yes, Robert does learn to appreciate math more, but not in a "behave yourself better" way; even The Phantom Tollbooth always has a bit of that "Milo, smarten up" aura around it. The Number Devil just happens to show up and make life...or at least dreams...more interesting, and you learn something at the same time.
I like the fact that several of the math threads continue throughout the book, such as "Bonacci numbers" (what the Number Devil calls the Fibonacci sequence). I've seen too many books that give a page or so to things like that, and then it's off to something completely different and you never see them again. Robert's dreams have different topics, but they're definitely sequential...and they come back to a starting place, usually "one." (Who knew that "one" could be so interesting?) I also like the colourful diagrams; to my poor non-math-major's mind, they make some kind of sense. The dialogue is snappy, not patronizing, and doesn't get bogged down with what it's trying to teach; that in itself is worth a few stars.
I do agree with the reviews that complain a bit that the book doesn't always use standard terminology, although there is a sort of "translator" at the end. If a kid gets used to "Prima Donnas" (prime numbers) and "hopping" (squaring), he or she is going to have to get that straightened out eventually. But there are really only a few invented terms, so it's not too hard; no worse than when I was teaching my kids to read with words like "cab" and "bac." Who cared, at that point, that "bac" should have a k on it? It didn't mess them up permanently.
We'll miss the Number Devil when the dreams are over.
Highly recommended, probably for ages 10-14.