Today in 1850, the first US patent (US No. 7,074) for a push-key operated adding machine is issued to Dubois D. Parmelee of New Paltz, New York.
In 1886, William Burroughs founded the American Arithmometer Company to commercialize his “adding machine” that “could do the work of two or three active clerks,” according to The Bankers’ Magazine in 1894.
HP-65, the first programmable handheld calculator, was introduced as a $795 “personal computer” by Hewlett-Packard in 1974.