Go Forth And Multiply – Ethiopian multiplication

http://www.open2.net/home.html

“Ever wanted to forget about fractions? Wished you could throw your times tables away? Well, ‘Ethiopian multiplication’ could be for you. For thousands of years, traders in Ethiopia have used a seemingly bizarre system of multiplication that ignores some numbers and dismisses others as unlucky. Yet the system – which has also beren used in Russia and throughout the Middle East – works every time. Go Forth and Multiply explains how and why it works – and reveals a surprising connection between this ancient method and modern computer codes”