What is the calculator invented by Chinese people besides abacus?

What is the calculator invented by Chinese people besides abacus?

mental calculation or arithmetic
Hope to adopt

Why is the sentence "abacus, calculator and computer are all calculation tools"

The computer is not only a calculation tool, it can also judge. According to the results of calculation, it determines the direction of the program

How to use abacus?

There are many kinds of calculation tools used in the history of human beings, and the slide rule is one of the most widely used important calculation tools. As early as the early 17th century, the calculation tools showed a rapid development in western countries

With the popularity of electronic computers, wooden bead abacus is not very useful. I learned abacus when I was young, but now I forget the formula of abacus, one on one, two on two, three on five, two off two What is its complete formula?

One up one, two up two, three down five go two, four down five go one, five go five into one, six up one go five into one, seven up two go five into one, eight up three go five into one, nine up four go five into one
You don't have to memorize pithy formula by rote. Just think about it and you can remember it
The top bead represents 5 and the bottom bead represents 1