Confucius was a citizen of LU. One day, the king wanted him to take care of the finance of Lu. Confucius was not good at this point. For this reason mistakes took place repeatedly. Afterwards, his wife taught him a way to solve this matter by making knots on a cord. That is to say when money comes in you tie a knot, when money goes out you undo a knot. After that, Confucius developed it into balls on poles with a frame around and the ancient abacus came into being at that moment.
From then on, the whole world started using it for calculation. And it is used by many people even now. There are also some people who collect old abacus because abacus has a long history and is very famous in the world.