1256-1321

Arab mathematician and astronomer who was the first to treat a fraction as a ratio of two numbers, and the first to use the term almanac (al-manakh, or "weather," in Arabic) for a book of astronomical data. Al-Banna, who spent most of his career in Morocco, wrote some 82 books on a number of subjects, including an algebraic treatise and an introduction to the Elements of Euclid (c. 325-c. 250 B.C.). His most important mathematical writings were Talkhis amal al-hisab (Summary of arithmetical operations), and Raf al-hijab, a commentary on the Talkhis.