Massimo on X: "#Today in 1972, Hewlett-Packard introduced the HP-35, the first scientific handheld calculator and the final step in ending reliance on slide rules among scientists and students. The HP-35 was
HP 35 - The world's first pocket scientific calculator from 1972 - YouTube
The HP 35 calculator
HP-35 - Wikipedia
Amazon.com: HP 35s Scientific Calculator : Electronics