Although it is unknown precisely who invented the abacus, the device was developed in China around 3000 B.C. It is highly compact and easy to use and forms the basis for modern calculators and computers.
There are many predecessors to the abacus, including containers of pebbles used as early as the Stone Age and clay boards with sliding grooves used in the Tigress-Euphrates Valley. Through cultural exchange and diffusion, these ideas spread around the world, eventually resulting in the Chinese abacus. The abacus is still used in many countries around the world. As late as 1946, a competition between an abacus and an electronic computer was won by the abacus.