From Greek 'abax' (counting board), probably from Hebrew 'abaq' (dust) — the first calculator was sand.
A simple calculating device consisting of a frame with rows of wires or grooves along which beads or stones are slid; used for performing arithmetic operations.
From Latin 'abacus' (counting board, calculating table), from Greek 'ábax,' genitive 'ábakos' (slab, board, calculating table). The Greek word is traditionally derived from Hebrew 'ābāq' (dust), referring to the earliest form of the device: a flat surface covered with sand or dust in which figures were drawn with a finger or stylus. The connection between dust and calculation reflects the most primitive form of mathematical notation: writing
Skilled abacus users can perform arithmetic faster than many people using electronic calculators. In 1946, a contest in Tokyo pitted a Japanese soroban (abacus) master against a US Army clerk using an electric calculating machine. The abacus won four of the five rounds, including the composite addition test of fifty numbers