Though it may be hard to imagine, but there was time when written numbers did not exsist. Early humans used pebbles, twigs, and their fingers as counting devices. The abacus was invented to help with counting the numbers before there were written. Merchants used it to help keep stock of their inventory and the cost of their goods.
The early abaci and the modern abaci are two very different things. The early abaci were called counting boards. "The counting board is a piece of wood, stone or metal with carved grooves or painted lines between which beads, pebbles or metal discs were moved. The abacus is a device, usually of wood (plastic, in recent times), having a frame that holds rods with freely-sliding beads mounted on them." The abacus and the counting board are both used as counting aids, not exactly calculators.
The evolution of the abacus can be summed up in three different time periods: Ancient Times, Middle Ages, and Modern Times. The earlist abaci were the Salamis Tablet(Greek), the Roman calculi and the Hand-abacus(Roman). The Salamis Tablet was first created in sometime from 300 to 500 B.C. In the Middle Ages (5 A.D. to 1400 A.D) the Apices, the coin-board, and the line-board were created. Around this time written numbers became more popular in Europe and the abacus was used less. In the Modern Times(1200 A.D. to present) the Suan-pan(Chinese), Soroban(Japanese), and the Schoty(Russian) were invented.
This is important to the computer revolution because the first computers were made to count numbers. Since the abaci were the first counting devices, humans were able to expand from them into possibly the greatest invention of all time.
