Abacus
The abacus was developed oi1 the basis of counters or chips. In the Spring and Autumn Period, chips were widely used in calculation. Chips of different colors represented different values, and they were placed in lines and columns to perform arithmetic calculations. Counters or chips were used in calculations in China for 2,000 years, but as social life progressed they failed to meet the requirements for calculating technique. The abacus was thus developed.
A Chinese abacus consists of a wooden frame with beads on parallel wires, and a crossbar
oriented perpendicular to the wires that divides the beads into two groups. Each column-that is, each wire-represents one place in the decimal system. The column farthest to the right is the ones column; the next column to the left is the tens column; and so on. In each column, there are five beads below the crossbar, each of which represent one unit, and two beads above the crossbar, each of which represent five units.
The principles and methods used in abacus calculations or calculations with beads are much the same as those used in calculations with chips, but the performance is faster and more convenient. The term zhu suan (calculation with beads) was first found in a work by mathematician Xu Yue of the Eastern Han Dynasty in the 2nd century AD. In Qing Ming Shang He Tu, a panoramic painting of life along the Bianhe River at Qingming festival by noted painter Zhang Zeduan of the Northern Song Dynasty, on the counter of a drug store was an abacus. Writer Tao Zongyi of the Yuan Dynasty first wrote about "the beads of abacus," saying "they are moved by hand." In Lu Ban Mu ling, a book on carpenter's work of the Ming Dynasty, there were quite a number of specifications for the making of abacuses. There were also books on the principles and pithy formulas used in abacus calculations. The most popular work on abacus calculating is Suanfa Tongzong (The Compendium of Calculating Methods) by Cheng Dawei (1533-1606). All this shows that the abacus was widely used in ancient China. The abacus as a calculating device is suitable for almost everyone, and even an illiterate can use it quite well.
Historical records show that different abacuses were developed in quite a few countries, but the Chinese abacus inherited the features of calculation with chips: the nine numbers and zero, the decimal system, and the ways the numbers and zero are represented. The Chinese abacus gradually spread to Japan, Korea, India, the United States and Southeast Asian countries. The abacus is still used as a counting aid, and in addition and subtraction calculations the abacus is faster than electronic calculators.
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