Eventually, the Sumerians made their writing more efficient, and slowly converted their picture words to a short-hand consisting of wedged lines created by bending the reed against the wet clay and moving the end closest to the hand back and forth once. All this administration of agriculture required much more careful planning, since each farmer had to produce a far greater excess of produce than he would actually consume. And all the bureaucratic record keeping demanded some kind of efficient system of measuring long periods of time. So the Sumerians invented calendars, which they divided into twelve months based on the cycle of the moon. This interest in measuring long periods of time led the Sumerians to develop a complicated knowledge of astronomy and the first human invention of the zodiac in order to measure yearly time.
Numbers have to be added up, subtracted, multiplied, divided, and sundry other fun things.
So the Sumerians developed a sophistication with mathematics that had never been seen before on the human landscape. We know very little about the early Semitic religions, but the Semites that invaded Mesopotamia seem to have completely abandoned their religion in favor of Sumerian religion. Sumerian religion was polytheistic, that is, the Sumerians believed in and worshipped many gods. These gods were incredibly powerful and anthropomorphic , that is, they resembled humans. Many of these gods controlled natural forces and were associated with astronomical bodies, such as the sun.