The decimal system

UNESCO Courier, Oct, 1988

The decimal system, now fundamental to modern science, originated in China. Its use can be traced back to the fourteenth century BC, the archaic period known as the Shang Dynasty, though it evidently was used long before that.

An example of how the ancient Chinese used the decimal system may be seen from an inscription dating from the thirteenth century BC, in which "547 days" is written "Five hundreds plus four decades plus seven of days".

In computation, the Chinese used counting rods on counting boards. To "write" ten involved placing a single rod in the second box from the right, and leaving the first empty, to signify zero. To change the ten to eleven, a single rod was added in the first box. To 'write' 111, single rods were placed in the first, second and third boxes. Apparently from the earliest times, the decimal place system for numbers was literally a place system; the Chinese placed counting rods into actual boxes.

The fact that the decimal system existed from the very beginning of mathematics in China gave the Chinese a substantial advantage, laying a foundation for most of the advances they later made.