The earliest abacus dates to 2700 BC when it was used in Mesopotamia to calculate the Sumarian sexagesimal number system. Over the millennia, it was used in various forms by the Egyptians, Persians, Greeks, Chinese, Romans, and many other civilizations. It is still used today as a teaching aid in many preschools and elementary schools. This abacus pendant (with moving steel beads!) represents both a love of mathematics and an important piece of math history. It will delight math teachers and students alike! The steel abacus measures 1 1/4 inches long and 3/4 inches wide, and has working steel beads. It comes with a 23 inch steel ball chain.