Arithmometer
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The arithmometer was the first digital mechanical calculator strong and reliable enough to be used daily in an office environment. This calculator could add and subtract two numbers directly and perfo
Arithmomètre built by Louis Payen around 1887
Detail of an arithmometer built before 1851. The one-digit multiplier cursor (ivory top) is the leftmost cursor
One of the first machines with a unique serial number (10-digit machines with serial numbers from 500 to 549) built around 1863
Front panel of a Thomas arithmometer with its movable result carriage extended
Comptometer
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The comptometer was the first commercially successful key-driven mechanical calculator, patented in the United States by Dorr Felt in 1887.
Arithmometer
…mechanical calculator industry. While in 1890 the arithmometer was still the most-produced mechanical calculator in the world, by 1900 four machines, the comptometer and Burroughs' adding machine in the USA, Odhner's Arithmometer in Russia, and Brunsviga in Germany had passed it in volume of machines manufactured…
Prototype of the first all-electronic desktop calculator marketed by Sumlock Comptometer Ltd of the UK
The macaroni box (1885)
Model A (1905)
Model J (1930s)