The early calculating instrument we know as the abacus—consisting of a wooden frame supporting wires or rods on which wooden beads slide from side to side—was developed in Mesopotamia from a flat, sand-covered, stone counting board on which pebbles were moved. This aid to calculation was in use long before the adoption of the Hindu-Arabic numeral system and can be adapted to any numeral base. The abacus has a huge advantage over counting on the fingers of the hand, simply because it can be used to record very large numbers accurately.
The easiest type of abacus to understand is the modern Western version that uses a base often. Here each wire carries ten beads and represents a decadal unit, that is one, ten, 100, 1,000 and so on. A number, say 617,483, can be represented by positioning the respective number of beads, on each wire, against one side of the
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