The Sumerians were the first people to develop a system of arithmetic. Adding, subtracting and multiplying were important skills when handling goods such as grain or cattle in any quantity. The Sumerians also developed an efficient system of weights and measures and their supreme invention - that of writing - arose from the practical need to keep records of goods for the purposes of trade or tax collection.

Those records began in the simplest of forms - picture images of the item - an ox head, for example - and a number of dots to indicate the quantity. Symbols were drawn on a soft clay tablet using a sharpened reed. The tablet was then baked in a kiln to harden it. Originally lists of items were arranged in vertical columns starting from the top right hand side. Around 3000 BCE, however, scribes found that they could write better by turning the tablets and writing from left to right, in horizontal rows.

At the same time, the original, pointed stylus was abandoned in favor of one with a wedge shaped tip. Scratching with a point was prone to leave untidy ridges; the new wedge shaped stylus could be pressed into the clay to leave a crisper impression. Stylized images, composed entirely of cuneiform, or 'wedge shaped' marks made up the writing system used in Mesopotamia.

By about 2500 BCE, the original picture signs were reduced to such stylized symbolism that the original objects could hardly be recognized. The scribes also started to use characters to represent ideas, actions, feelings and so on, rather than just concrete objects alone. Ambiguities began to creep in and sometimes resulted. The picture image of a foot, for example, might mean to come or go or stand and so on. Thousands of different characters were invented to encompass the full range of words in use.

The eventual solution was to use signs phonetically - to indicate sounds rather than actual object. Using a fairly limited repertoire of syllables it was possible to build up most any word. The Sumerian system included some 600 - 700 signs which had to be memorized. The system was not condensed further by breaking syllables down into the two dozen or so letters that make up our modern day alphabet but their own method proved remarkably flexible. It permitted a rich literature to flourish alongside workday texts such as bills of sale and legal contracts. The Sumerian system of arithmetic was based on the unit of 60 and has survived through the centuries in our hour of 60 minutes and circle of 360 degrees.