Arabic numerals are the characters 1, 2, 3, 4, 5, 6, 7, 8, 9 and 0. They are by far the most common symbols used to represent numbers and are considered to be one of the most significant developments in the history of mathematics.
Arabic numerals derive their name from the fact that they were long used in the Arab countries. This name has also served as a convenient way to distinguish them from the Roman and Greek numeral systems that were native to Europe. Actually, however, similar numerals were in use in India before they spread to the Arab countries; they may have originated in India, or there may have been some common source for them as well as the Chinese numerals1.
The biggest reasons for the popularity of the Arabic numerals are their simplicity (including their simple shapes and consequent ease and speed of writing) and their suitability for calculation. Fundamental to the latter are, in addition to their simplicity, the use of a single character for each numeral (in contrast to multiple characters required to represent numerals larger than five in the Roman system) and the availability of a zero.
Several other systems to represent numbers are also in common use. The most widely utilized of these is the Chinese system, which is employed not only in China, but also in Japan and Korea. In all of these countries this system is used along with the Arabic system, with the choice of system depending on the particular context2.
Despite the great convenience of Arabic numerals, computers do not use them for their internal calculations (at a fundamental level everything that a computer does is a calculation). Rather, computers use the binary system, which is only concerned about two alternative states (e.g., zero and one, or no and yes) because this is by far the most efficient system for their digital circuitry. They are not concerned about any particular glyphs (i.e., visual representations) for numbers, and they use Arabic numerals only for their interfacing with humans (mainly on keyboards and display screens). This is, of course, because the base ten system (e.g., Arabic numerals, Chinese numerals and Roman numerals) is far easier for humans to understand than is the binary system.
2This is somewhat analogous to the situation in English and many other languages in which the decision as to whether a number should be written with Arabic numerals or Roman letters (e.g., 12 or twelve) depends on the context and certain standardized rules of writing.
Created March 25, 2006.