Chinese abacus

The abacus is an abacus (calculating tool) consists of a rectangular frame fitted with rods on which balls slide.

The abacus is linked to the system of decimal numeration each ball, according to the stem on which it is a unity, a dozen, a hundred ... bouliers Some include special balls worth 5 units, 5 tens, 5 hundreds ...

The bouliers used to perform calculations: addition, subtraction, multiplication, division. In expert hands, it is possible to perform other operations such calculations nth roots or conversion to different bases.

There are several types:

* The Chinese abacus or suan pan. It is used in China for over 8 centuries. There are an illustration on a book dating from the twelfth century. On each stem, there are 5 balls for a unit and 2 scoops of 5 units, separated by a central bar.
* The Japanese Soroban abacus. In Japan it appears to the fourteenth century probably imported from China. He gradually lost, compared to the Chinese abacus, two balls (a ball of value 1 and a ball of value 5).
* The Russian abacus or stchoty (Счёты), also used in some Iranian as Chorèbe and Turkey under the name coulba is composed of stems 10 balls worth 1
* The abacus-counter use French in French schools until the eighteenth century, probably variant of the Russian instrument.

It is remarkable in the era of the electronic calculator, the great importance that it retains computing across Asia. It is not uncommon to see Russian or Asian traders make a calculation with a calculator and check the results using the abacus. In expert hands, it is tremendously efficient. In 1945, a match between an accountant with a Japanese Soroban operator and a power calculator (Matsuzaki against Woods) was won by the soroban by a score of 4 to 1.
Playing a number

Each column is from the right, units, tens, hundreds etc.. The 5 balls below each worth 1 and 2 balls on top of the bar are worth 5 each.