## The History of Mathematics## Mesopotamian Numbers and Mathematics |

## How did the Sumerian written counting system change over time? |

Around 3200 B.C.E., the Sumerians began a written number system, attaching a special graphical symbol to each of the larger numbers at various intervals (1, 10, 60, 3600, etc.). Because of the rarity of stone, and the difficulty in preserving leather, parchment, or wood, the Sumerians used a material that would not only last, but would be easy to imprint: clay. Each symbol was written on wet clay tablets, then baked in the hot sunlight. This is why many of the tablets are still in existence today.

The Sumerian number system changed over the centuries. By about 3000B.C.E., the Sumerians decided to turn their numbering symbols counterclockwise by 90 degrees. And by the 27th century B.C.E., the Sumerians began to physically write the numbers in a different way, mainly because they changed writing utensils from the old stylus that was cylindrical at one end and pointed at the other to a stylus that was flat. This change in writing utensils, but not the clay, created the need for new symbols.

The new way of writing numbers was called *cuneiform script,* from the Latin *cuneus,* meaning “a wedge” and *-formis,* meaning “like.”