Before the invention of micro chips and vacuum tubes there were Mechanical calculator's, which were on every desk from the early 1900's to the 60's. These devices were motor-driven, and had movable carriages where results of calculations were displayed by dials.In these machines, Addition and subtraction were performed in a single operation, as on a conventional adding machine, but multiplication and division were accomplished by repeated mechanical additions and subtractions.

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Via - Hemmy and Wikipedia