## A quotation by Al-Khwarizmi

That fondness for science, ... that affability and condescension which God shows to the learned, that promptitude with which he protects and supports them in the elucidation of obscurities and in the removal of difficulties, has encouraged me to compose a short work on calculating by

*al-jabr*and

*al-muqabala*, confining it to what is easiest and most useful in arithmetic.

[

*al-jabr*means "restoring", referring to the process of moving a subtracted quantity to the other side of an equation;

*al-muqabala*is "comparing" and refers to subtracting equal quantities from both sides of an equation.]

The Arabs contributed nothing new to the theory, but al-Khowirizmi (c. 825) states the usual rules, and the same is true of his successors.

David Eugene Smith.

*History of Mathematics*(1923)