Casio (1s, 10s, 100s, etc ... ) had nine keys. Another distinguishing innovation was the use of a single display window instead of the three display windows (one for each argument and one for the answer) used in other calculators. Casio Computer Co., Ltd. was formed in June 1957. That year, Casio released the Model 14-A, sold for 485,000 yen, the world's first all-electric compact calculator, which was based on relay technology. In the 1980s, its budget electronic instruments and its line of affordable home electronic musical keyboard instruments became popular. The company also became well known for the wide variety
Sinclair Wrist Calculator Sinclair Wrist Calculator The Sinclair Wrist Calculator was a wrist-worn calculator produced by Sinclair Instrument and introduced in 1977. The Wrist Calculator was launched in February 1977 by Sinclair Instrument, a company established in parallel to Sinclair Radionics when the latter started to encounter financial difficulties. It was only available as a mail-order kit, and cost around . Despite the difficulty in assembling the kit due to the small size of the parts and their variability in specification, 10,000 were sold around the world. 20,000 were exported to the United States, but most went unsold and were returned to Sinclair.