When I showed this book to my seven-year-old math monster, he wouldn't let me stop reading it. I read most of the book to him over about 3 hours, with discussions and figuring out some of the little puzzles at the end. Then, first thing this morning he stuffed the book back in my hands. I'm sure my voice will feel better tomorrow, and the things I learned will last a lot longer. He wouldn't let me stop reading enough to play the games that used paper and scissors until I had read everything. He's doing them now. Maybe when my throat recovers I'll tell him I also bought another book by this author.