Algorismus is a short treatise on mathematics, written in Old Icelandic. It is the oldest text on mathematics in a Scandinavian language and survives in the early fourteenth-century manuscript Hauksbók, a large book written and compiled by Icelanders and taken to Norway during the later part of the 13th century by Haukur Erlendsson. It primarily consists of a translation of Carmen de Algorismo by Alexander of Villedieu from , which was in turn translated from the works of al-Khwarismi, and which, with Liber Abaci by Fibonacci of 1202, and Algorismus Vulgaris by De Sacrobosco of 1230 formed the "three main Latin algorithmic works in the Middle Ages".
References See section 3.12 Algorismus, pp. 63–65, which calls it "one of the most important mathematical treatises in medieval Iceland".