# The Number Devil: A Mathematical Adventure by Hans Magnus Enzensberger

Standard

Enzensberger, Hans Magnus. The Number Devil: A Mathematical Adventure. Picador, 2000. ISBN 978-0805062991 264 pp. \$13.99

*****

What do you get when you cross Alice in Wonderland with a small, red, horned man obsessed with numbers? No, it isn’t an arithmetic problem–it’s a middle school math primer!

Robert, a boy who hates math and is frustrated because his teacher doesn’t allow calculators, has strange dreams all the time. One night he dreams up a character called the Number Devil, who takes him away to a surreal world of numbers where Robert learns basic math concepts and a few handy shortcuts. After all, says the Number Devil, “you learn best when you sleep.”

Over the course of twelve different evenings, Robert learns factorials, how to find a square root, and more. Concepts such as the importance of the number zero and the idea of infinity are stressed over and over. Robert discovers triangle number, Bonacci numbers, imaginary numbers, and irrational numbers. Did you know that you can take any even number larger than two and find 2 prime number that add up to it? Robert is even able to apply what he’s learned in an actual math class.

The Number Devil makes up fun–and punny–terms for things. Roots become “rutabagas” (a root vegetable) and prime numbers are “prima donnas.” Squaring becomes “number hopping,” and factorials (!) are renamed “vrooms.” A warning at the end reminds kids to use the proper terms in class. The index doubles as a brief glossary, defining terms in a few words.

It is truly remarkable how clearly the theories are presented. Enzensberger translates math to German, and Berner translates the German to English. The concepts are well explained and provide jumping off points for many discussions, from pyramids to mosaics to biographies of mathematicians.

Whimsical illustrations and colorful charts and diagrams add to the text. Practical applications relate to nature in many cases. Bonacci numbers are illustrated with rapidly multiplying bunny rabbits. Similar examples would have been great! Related activities include playing with number triangles and making 3-D geometric shapes. There are no pages of practice problems or exercises, although one or two chapters end with a question for a student to solve by extrapolating new information.

Middle school teachers can spice up their lectures with a chapter from this book. Homeschoolers can it as a unique supplemental text. While some might object to the negative imagery surrounding math (Robert is in number hell, and learns from a devil), the book may reach some kids relate to the main character. This math-phobic librarian (the only numbers I’m good at are Dewey Decimal ones) can’t wait for the sequel!