Abacu wa invented by Chinee----Confuciu. It ha a long hitory. Now, let me tell you about how abacu wa invented.
Confuciu wa a citizen of LU. One day, the king wanted him to take care of the finance of Lu. Confuciu wa not good at thi point. For thi reaon mitake took place repeatedly. Afterward, hi wife taught him a way to olve thi matter by making knot on a cord. That i to ay when money come in you tie a knot, when money goe out you undo a knot. After that, Confuciu developed it into ball on pole with a frame around and the ancient abacu came into being at that moment.
From then on, the whole world tarted uing it for calculation. And it i ued by many people even now. There are alo ome people who collect old abacu becaue abacu ha a long hitory and i very famou in the world.