Algorism is the technique of performing basic arithmetic by writing numbers in place value form and applying a set of memorized rules and facts to the digits.
The word algorism comes from the name Al-Khwārizmī (c. 780–850), a Persian[2][3] mathematician, astronomer, geographer and scholar in the House of Wisdom in Baghdad, whose name means "the native of Khwarezm", which is now in modern-day Uzbekistan.
[7] Al-Khwarizmi was the most widely read mathematician in Europe in the late Middle Ages, primarily through his other book, the Algebra.
[8] In late medieval Latin, algorismus, the corruption of his name, simply meant the "decimal number system" that is still the meaning of modern English algorism.
It begins thus: Haec algorismus ars praesens dicitur, in qua / Talibus Indorum fruimur bis quinque figuris.which translates as: This present art, in which we use those twice five Indian figures, is called algorismus.The word algorithm also derives from algorism, a generalization of the meaning to any set of rules specifying a computational procedure.