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HP-35 Scientific Calculator Awarded IEEE Milestone

14 April  –  IEEE, the world’s largest technical professional association, announced that it has named the HP-35 scientific calculator as an IEEE Milestone. Introduced in 1972, the HP-35 was the world’s first handheld-sized scientific calculator which ultimately made the slide rule, which had previously been used by generations of engineers and scientists, obsolete.

Before the development of the HP-35, contemporary calculators could only perform four basic functions – addition, subtraction, multiplication and division. The HP-35, named for its 35 keys, was the first handheld calculator to perform trigonometric, logarithmic, exponential and other transcendental functions.  The now classic “Reverse Polish Notation” (RPN) first used in the HP-35 has become the most efficient way known to computer science for evaluating mathematical expressions.

An IEEE Milestone plaque will be permanently displayed at HP Labs in Palo Alto, Calif., the site where the HP-35 was originally developed.

Read the full press release. (PDF, 40 KB)