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
Busicom subsequently "Broughtons & Co.(Bristol) Ltd" of the UK. The "Nippon Calculating Machine Corp" was incorporated in 1945 and changed its name in 1967 to "Business Computer Corporation", Busicom. Due to a recession in Japan in 1974, Busicom became the first major Japanese company in the calculator industry to fail. Originally, they made Odhner type mechanical calculators and then moved on to electronic calculators always using state of the art designs. They made the first calculator with a microprocessor for their top of the line machines and they were the first to make calculators with an all-in-one calculator chip, the Mostek