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
Marchant calculator known as SCM, tried to stay competitive by introducing the SCM Cogito 240SR electronic calculator (designed by Manhattan Project veteran Stan Frankel) in 1965. Within a few years a tidal wave of cheaper electronic calculators had devastated their business, and by the mid-1980s, SCM's typewriter business, too, had been ruined by the advent of inexpensive personal computers used as word processors. The first Marchant calculators differed greatly from their later Silent Speed Proportional Gears machines, which were by far the fastest of their type, running at 1,300 cycles per minute. These machines are of considerable technical interest, and are far