Abacus is one of the earliest counting device and one of the most brilliant inventions by man.
What is an abacus?
An abacus is a device used for addition and subtraction, and the related operations of multiplication and division. It does not require the use of pen and paper, and it's good for any base number system. There are two basic forms for the abacus: a specially marked flat surface used with counters (counting table), or a frame with beads strung on wires (bead frame).
The name Abacus derives from the Greek word ABAX meaning table or board covered with dust. The origins of the Abacus are buried deep in the history of mankind. But it is generaly assumed that the origins of the Abacus lies in the Middle East some where in the period known as the Early Middle Ages. The model developed during that period had a wooden frame with several wires each strung with 10 beads. Three more than the Abaci we know now from Asia.
Here is a link where you could read more about abacus. You could also read here inventions that are created because of the abacus
