Because the numbering systems of the Mesopotamians, Babylonians, Egyptians, Greeks and Romans are not convenient for extensive calculation, it is believed that they used some sort of mechanical calculating device. The simplest form of calculating device is a kind of table or tablet on which calculation can be written in sand or dust, and then easily erased. This is the "sandboard abacus". One derivation of the Latin word abacus comes from the Greek abakos from the Hebrew word abaq, meaning dust.
In his Histories Herodotus of Halicarnassus, written about this time, stated that the Egyptians "write their characters and reckon with pebbles, bringing their hand from right to left, while the Greeks go from left to right." D.E. Smith, in his History of Mathematics II, p. 160 quotes this statement by Herodotus and writes, "Right to left order was that of the hieratic script and there is probably some relation between this script and the abacus. No wall pictures thus far discovered give any evidence of the use of the abacus, but in any collection of Egyptian antiquities there may be found disks of various sizes which may have been used as counters."