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
Calculator and built at the Elektronika factory in Sofia. The name derives from "ELektronen KAlkulator", and it weighed around . It is the first calculator in the world which includes the square root function. Later that same year were released the ELKA 22 (with a luminescent display) and the ELKA 25, with an in-built printer. Several other models were developed until the first pocket model, the ELKA 101, was released in 1974. The writing on it was in Roman script, and it was exported to western countries. The "Monroe Epic" programmable calculator came on the market in 1967. A large, printing,