Al-Karaji
Persian mathematician and engineer (c. 953 – c. 1029)
Abū Bakr Muḥammad ibn al Ḥasan al-Karajī (Persian: ابو بکر محمد بن الحسن الکرجی; c. 953 – c. 1029) was a 10th-century Persian mathematician and engineer who flourished at Baghdad. He was born in Karaj, a city near Tehran. His three principal surviving works are mathematical: Al-Badi' fi'l-hisab (Wonderful on calculation), Al-Fakhri fi'l-jabr wa'l-muqabala (Glorious on algebra), and Al-Kafi fi'l-hisab (Sufficient on calculation).
Work
Al-Karaji wrote on mathematics and engineering. Some consider him to be merely reworking the ideas of others (he was influenced by Diophantus) but most regard him as more original, in particular for the beginnings of freeing algebra from geometry. Among historians, his most widely studied work is his algebra book al-fakhri fi al-jabr wa al-muqabala, which survives from the medieval era in at least four copies.
He expounded the basic principles of hydrology and this book reveals his profound knowledge of this science and has been described as the oldest extant text in this field.
He systematically studied the algebra of exponents, and was the first to define the rules for monomials like x, x2, x3 and their reciprocals in the cases of multiplication and division.
“Al-Karaji” enters the record as persian mathematician and engineer (c. 953 – c. 1029). Crown Archives preserves that source wording while asking what Al-Karaji, Persian and mathematician can confirm, complicate or overturn.
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Biographical claims are most persuasive when dates, appointments and relationships can be traced to records created close to the events described. The source revision retrieved here is dated Sep 8, 2026. The linked authority identifier is Q461062. VIAF identifies the subject as 46856646. The Library of Congress control number is n88627122. 3 of 3 selected statements include explicit references; 0 carry qualifiers and 0 use preferred rank. The first chronological checks are 1029.
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This entry incorporates text from “Al-Karaji” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.