The earliest development of mathematics is closely tied to the development of counting and numbers. For thousands of years before there was a system for writing numbers, ancient people used a variety of methods to either estimate or guess at the amounts of things they dealt with in their daily lives. At some point, they began to invent ways of keeping a tally of their possessions, such as livestock or sacks of grain. The simple methods for doing this varied widely from one part of the world to another, from civilization to civilization, but inevitably they led to the development of numbers. The first we know about came from Sumeria (around the area now known as Iraq) about 3000 B.C. Number systems also varied from one area to another, just as the early Sumerian system was very different from what we use today, but...