The speed of mental arithmetic is amazing. Often, as long as you hear the number of questions or see the calculation questions yourself, the calculator can blurt out the answers or write them out immediately. Therefore, abacus mental center is an advanced computing technology.
origin
"The family of seven, separated by two lines, everything is vicissitudes. All corners of the country, three religions and nine streams of beads are busy. "
The word "abacus calculation" first appeared in Xu Yue's Notes on Numerology in Han Dynasty, among which "abacus calculation controls three talents at four seasons" is said.
After the evaluation of UNESCO, abacus was officially listed in the list of intangible cultural heritage of mankind, which brought this ancient invention, which is gradually drifting away from modern society, back to people's field of vision. As an ancient computing tool and skill, it has been with China people for 1800 years.