Counting and the abacus
Because ancient numeral systems and methods of recording were unsuitable for calculation, it was inevitable that some kind of physical or mechanical aids to calculating would be developed. The first to appear was the dust or sand abacus whcih was a table covered with dust or sand on which figures were drawn with a stylus and erased with the finger. It was used for writing and recording.
This evolved into the line or counter abacus in which counters were moved along lines or grooves drawn on a table. These counters were often pebbles (calculi) and the lines represented powers of 10. This abacus was commonly used for calculation in Egypt, Greece and Rome, and in Europe until the 16th 
century.
The familiar bead abacus was developed in the late Middle Ages in China (the suan-pan), in Japan (the soroban) and in the Arab Near East (the choreb and coulba). It was then introduced into Russia (the s’choty) where it is still used today.
