- Sideways Arithmetic from Wayside School by Louis Sacher.

Louis Sacher is the author of the very popular Wayside School series; our kids have loved these books. This Sideways Arithmetic book consists of "50 mindboggling math puzzles". For example, the first puzzle in the books is: elf + elf = fool. The problem in this case is to identify the number that each letter stands for. - The Number Devil by Hans Magnus Enzensberger.

This book looked even more interesting. It's about a young boy who visits a "...bizarre magical land of number tricks with the number devil as his host." And in this land, kids are introduced to all kinds of mathematical concepts including prime numbers ("prima donnas"), irrational numbers ("unreasonable"), and roots ("rutabagas"). Sounds fun and educational!

And for older kids (or adults like me!), he recommended "What is Mathematics?" by Richard Courant (after whom NYU's Courant Institute is named) et al. This was a book originally published in 1941, and recently revised in 1996! Any book in print since 1941 has to be a classic. This isn't a book about mathematics (in the sense that it isn't about the philosophy of mathematics or about meta-mathematics). Rather, it provides an elementary approach to the ideas and methods of mathematics. Albert Einstein apparently said of this book "A lucid representation of the fundamental concepts and methods of the whole field of mathematics...Easily understandable"!

I think I'm going to get all three books (for my kids and for me!) and check them out.