Abacus

The abacus stores a number as the positions of movable markers, with each rod or row standing for a place value, so the frame is a memory and the fingers are the processor. Its forms vary, from the Chinese suanpan with two beads above the bar and five below to the Japanese soroban with one above and four below, but the principle is the same. It is no museum piece. In a 1946 contest in Tokyo, a postal worker using a soroban beat an American soldier with an electric calculator in four of five rounds. Start here to see why place value, not gears, is the real foundation of every machine further down this list. Even the shop counter is named after the counting boards that sat on it.