With the discovery of electricity and the invention of the electric motor, it was inevitable that someone would eventually create an electro-mechanical calculator …

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It’s difficult to pin this sort of thing down, but it’s generally accepted that the first motor-driven calculating machine was the Autarith, which was created in 1902 by the Czechoslovakian Alexander Rechnitzer and manufactured by the Autarith Company in Vienna, Austria.

Other manufacturers soon followed. In the early versions of these devices, the motor ran continuously and it was only brought into play by a clutch mechanism when the actual calculation was to be performed. Later models were designed such that their motors only ran while an operation was being performed.

Motorized versions were created for most of the main mechanical calculator families, including Thomas-type and Odhner-type machines. For example, consider the MADAS calculator shown in Figure 25, where the name "MADAS" is derived from the initial letters of "Multiplication, Automatic Division, Addition, and Subtraction."


In addition to a Comptometer-style keyboard, this MADAS featured a mechanical, electrically driven, stepped-gear system that could perform the four basic functions of addition, subtraction, multiplication, and division (accompanied by a lot of “whirring” and “clunking”). Numbers could be entered to ten places of decimals and the accumulator (shown at the top) could present a result to 20 places of decimals.

Casio and the 14-A
By the 1940s, mechanical calculators driven by electric motors were very common in business and engineering environments. In 1946, the Japanese engineer Tadao Kashio founded a company called Kashio Seisansho. Initially this company manufactured products such as aircraft parts, but some time after its inception, Tadao’s brother Toshio proposed that they developed an electromechanical calculator.

Unlike existing electromechanical calculators, which were essentially standard mechanical calculators augmented with electric motors, Tadao and his three brothers decided that their calculator would be based on relays. Looking something like a cross between a desk and a credenza with the user input and display mechanisms presented in a raised unit to one side - their first offering – the Model 14-A – was presented to the market in 1957 (the “14” indicated fourteen digits of precision and the “A” was intended to show that this was the first in the series).

At the same time, the brothers also formed a new company to manufacture, market, and develop their calculator products. This company was the Casio Computer Co. Ltd., which was destined to become a major player with regards to electronic calculators (and a variety of other electronic products) in the not-so-distant future.

Note: The material presented here was abstracted and condensed from The History of Calculators, Computers, and Other Stuff document provided on the CD-ROM accompanying our book How Computers Do Math (ISBN: 0471732788).