Abu Bakr al-Hassar, 11th century Muslim mathematician who first used the fraction bar, also called the vinculum.
Al-Hassār, a Moroccan mathematician from Fez specializing in Islamic inheritance jurisprudence during the 12th century, first mentions the use of a fractional bar, where numerators and denominators are separated by a horizontal bar.
Sidi Hajjaj Oued Hassar is a small town and rural commune in Kénitra Province of the Grand Casablanca region of Morocco.