Because we have ten fingers, grouping by ten seems natural, but it has serious shortcomings. Twelve would be better for divisibility, and eight is well suited to repeated halving. Grouping by two, as in binary code, has turned out to have its own remarkable advantages.

Paul Lockhart presents arithmetic not as a rote manipulation of numbers-a practical if mundane branch of knowledge best suited for filling out tax forms-but a fascinating, sometimes surprising intellectual craft that arises from our desire to add, divide, and multiply important things. Passionate and entertaining, Arithmetic invites us to experience the beauty of mathematics through the eyes of a beguiling teacher.

"Inspiring and informative ... deserves to be widely read."
-Wall Street Journal

"A nuanced understanding of working with numbers, gently connecting procedures that we once learned by rote with intuitions long since muddled by education...Lockhart presents arithmetic as a pleasurable pastime, and describes it as a craft like knitting."
-Jonathon Keats, New Scientist

"This fun book offers a philosophical take on number systems and revels in the beauty of math."
-Science News

"What are numbers, how did they arise, why did our ancestors invent them, and how did they represent them? They are, after all, one of humankind's most brilliant inventions, arguably having greater impact on our lives than the wheel. Lockhart recounts their fascinating story...A wonderful book."
-Keith Devlin, author of Finding Fibonacci