Has anyone used (or heard of, at this point) Beast Academy books from Art of Problem Solving? These books are for younger kids (AoPS refers to the audience as up and coming "math beasts"). The books are so new, they haven't published the whole series yet.
I've been using book 3C with DD8. The first part is an introduction to pre-algebra. It goes over the idea of variables, transforming sentences into equations ("Twenty four minus a number is fifteen"; "Thirty-six is a 16 less than a number.") Subsequent sections go into long division and conversions.
The books are in full-color comic book format, and the characters are all monsters. They're surprisingly readable. There are also exercise books. Some of the exercises are quite original (e.g. a perfect square maze in book 3B where you have to trace a path from beginning to end by stepping on perfect squares; PEMDAS-type problems without the exponents).
Overall, I'm pretty impressed so far at what they cover, the depth they go into, and how they explain things. Has anyone else used them?
