Abacus is nearly 2500 years old. It is difficult to imagine counting without numbers, but there was a time when written numbers did not exist.
The earliest counting device was the human hand and its fingers. Then, as larger quantities (larger than ten human-fingers could represent) were counted, various natural items like pebbles and twigs were used to help count. Merchants who traded goods not only needed a way to count goods they bought and sold, but also to calculate the cost of those goods.
Until numbers were invented, counting devices were used to make everyday calculations. The abacus is one of many counting devices invented to help count large numbers. Abacus or abaci (plural of abacus) is a kind of calculator called “soroban” in Japan and “suan-pan” in China.
Abacus originally meant a “flat board” made of slate or wood. Many years ago people used the board for calculation by putting pebbles on it. It was not so easy for people to understand the concept of numbers so they started using tangible things such as pebbles, coins and beads for calculation. This led to the invention of abaci or soroban.
The modern Japanese abacus, called ABACUS was transfigured from the original Chinese abacus (suan-pan): two top beads and five bottom beads in a single column, to one top bead and four bottom beads in a single column. This was done in recent history, the middle of the 20th century (around 1930).