# The Number Devil by Hans Magnus Enzensberger

Suggested Audience: mid-elementary, upper elementary, middle school, high school

**(out of 5)**

Hans Magnus Enzensberger is a critically acclaimed and much loved author in his native Germany, and The Number Devil is one of his only books written specifically for younger readers. Before I get into the review I need to say, right up front, that I really, really love this book. OK, now for the review.

The title character in the book, the number devil, appears in the dreams of young Robert and has taken it upon himself to show him how math is far more, and far more interesting, than his teacher makes it seem. Through a series of dreams, night after night, the number devil introduces Robert to more and more sophisticated mathematical ideas ranging from prime numbers, infinity, Pascal’s Triangle, the golden mean, the Fibonacci sequence, and much, much more. In place of the actual mathematical names he uses whimsical names; in discussing imaginary numbers he refers to ‘imaginative numbers,’ and in place of prime numbers he says, ‘prima donna numbers.’ These are dreams, after all! Along the way, Robert progresses from being bored with math to being fascinated by it, and it’s clear that the author hopes that by the end of the book, the reader has developed a much greater love for and appreciation of math as well.

Enzensberger has done a magnificent job in writing this book, balancing just the right amount of humor and whimsy with accurate and meaningful mathematics. It’s a very accessible introduction to a number of fundamental ideas in number theory, and I think everyone should read this at some point in elementary, middle or high school.