The earliest computational tool

An abacus, also called a counting frame, is a calculating tool used primarily by the easterns for performing arithmetic processes. Nowadays, abaci are often constructed as a wooden frame with beads sliding on wires, but originally they were beads or small stones moved in grooves in sand or on tablets of wood, stone, or metal.

The abacus was in use for centuries before the adoption of the written modern numeral system and is still widely used by merchants and clerks in China, Japan, Africa, India and elsewhere. The user of an abacus is called an abacist; he or she slides the beads of the abacus by hand.