'Algorism' comprises all of the rules of performing arithmetic computations using a
decimal system for representing numbers in which numbers written using ten symbols having the values 0 through 9 are combined using a place-value system (
positional notation), where each symbol has ten times the weight of the one to its right.
This system superseded earlier, more verbose, decimal systems where the symbols were different for each power of ten (and repeated instances gave the quantity of each power of ten) because at most ten symbols were needed for any range of numbers. The other systems needed a new symbol for every power of ten (and up to nine copies of each symbol for each of these).
Starting with the integer arithmetic developed in India using ten symbols in this way, Arabian
mathematicians documented new arithmetic methods and made many other contributions to decimal arithmetic (including the concept of the decimal fractions as an extension of the notation, which in turn led to the notion of the
decimal point).
The word ''algorism'' comes from the name
al-Khwarizmi ("the one from
Khwarizm") of an early
9th century Persian mathematician, possibly from what is now
Khiva in western
Uzbekistan. In English, it was used by Chaucer in about 1230
[1]. Another early use of the word is from 1240, in a manual titled ''Carmen de Algorismo'' composed by
Alexandre de Villedieu. It begins thus:
"Algorism is the art by which at present we use those Indian figures, which number two times five."
The word devolved into the modified form ''
algorithm'', with a generalization of the meaning to any set of rules specifying a computational procedure. Occasionally ''algorism'' is also used in this generalized meaning, especially in older texts.
The place-value system
Algorism is based on the ten-symbol place value system, of which
Georges Ifrah wrote
[2]
See also
★
Hindu-Arabic numeral system
★
History of the Hindu-Arabic numeral system
References
1. Oxford English Dictionary (first quote ''c''1230CE, Chaucer ''c''1391, and later quotes showing continuing usage since then)
2. Ifrah, G. The Universal History of Numbers: From prehistory to the invention of the computer. John Wiley and Sons Inc., 2000. Translated from the French by David Bellos, E.F. Harding, Sophie Wood and Ian Monk