The earliest abacus dates to 2700 BC when it was used in Mesopotamia to calculate the Sumerian 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, all in a fun piece of jewelry. 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 in your choice of silver or gold. It comes with a 24 inch steel link chain.