Sperry and Remington had long and varied histories. Sperry Gyroscope Company was incorporated in 1929, and in 1933 Sperry Corporation was incorporated as a holding company of other small firms, including Sperry Gyroscope, Ford
Instrument Company, and Intercontinental Aviation, Inc. In 1955 it acquired Remington Rand, a company which was formed in 1927 by combining Remington Typewriter Company, Rand Kardex Bureau, Inc., the Dalton Adding Machine
Company, the Safe Cabinet Company, and the Powers Accounting Machine Corporation. Sperry Gyroscope was interested in Remington Rand because of the UNIVAC, the first commerically available computer, which Remington Rand produced
and delivered to the U.S. Census Bureau in 1951. In 1986 Sperry Corporation merged with Burroughs Corporation to form Unisys. (Information from the Burroughs Corporation Collection)
For more information on Sperry-Remington calculators see the article "From ENIAC to Calculator" in the Collecting Calculators section of this site.
There were many calculators which, to save cost, only had a 6-digit display (the Royal Digital III only had a 4-digit display!). Most also had the extra key to
reveal the less-significant digits.