Calculator watch Calculator watch A calculator watch is a digital watch with a built in calculator, usually including buttons on the watch face. Calculator watches were first introduced in the 1970s and continue to be produced, despite falling from their peak popularity during the 1980s. The most notable brand is the Casio Databank series, though watches made by Timex were also popular. Most calculator watches contain only a few number of functions such as +, -, x, / and percents. However, there are several models with additional functions: scientific, including transcendent and trigonometry, in models Casio CFX-200, CFX-400, Citizen 49-9421, and also
The Millionaire Calculator computations. This machine was very big and heavy and occupied an entire desk. Its size made it awkward to operate. It was commercialized as "The Millionaire" in English speaking countries, "La Millionnaire" in French and "Millionär" in German speaking countries. The Millionaire Calculator The Millionaire calculator was the first commercially successful mechanical calculator that could perform a direct multiplication. It was in production from 1893 to 1935 with a total of about five thousand machines manufactured. The principle of a calculation machine with progressive transmission of tens was invented by Chebyshev and demonstrated at the 1878 World's fair in Paris.