A cuneiform mathematical text from Hammurabi's time. Most mathematical texts come from a site at Tell Harmel in modern Iraq and are primarily school assignments used to instruct students. Many are tables for multiplication, division, finding cubic measurements or calculating weights. The Babylonian number system used the number sixty as a base. The cunieforms on this tablet are not identified. Cuneiform script is one of the earliest known forms of written expression. Emerging in Sumer around the 30th century BC, with predecessors reaching into the late 4th millennium, cuneiform writing began as a system of pictographs.