Most contemporary calculators could only perform the four basic operations – addition, subtraction, multiplication, and division. The "35" in the calculator's name came from the number of keys. We sold 100,000.". The key bottoms were designed to be easy on the copper while still providing the right feel which is essentially unchanged in current calculators. more than 300,000 had been sold. The HP-35 was 5.8 inches (150 mm) long and 3.2 inches (81 mm) wide, said to have been designed to fit into one of William Hewlett's shirt pockets. The HP-35 was the start of a family of related calculators with similar mechanical packaging: Follow-on calculators used varying mechanical packaging but most were operationally similar. HP-35 calculators were used on the US space station, Is the first pocket calculator with a numeric range that covered 200 decades (more precise 199, ±10. webmaster, Take this product for an interactive spin. The. Sinclair’s calculator range expanded tremendously in the early 1970s, with many models available both pre-built and in slightly cheaper kit form. He stressed how important it was to get the calculating power of the desktop in his fingers. The HP-35 performed all the functions of the slide rule to ten-digit precision over a full two-hundred-decade range. It was the first calculator to offer alphanumeric capabilities for both the display and the keyboard. Was the first scientific calculator to fly in space in 1972. again in 1971 to take that desktop computer and make it small enough The microcode word length was 11 bits; during final development shortened to 10 by having only an inferred conditional branch, a ten percent reduction in circuitry was significant at the time. and scientists for rapid calculation and simple computation. "HP-35 Scientific Calculator Awarded IEEE Milestone", "Retro HP 35s Launched to Commemorate 35th Anniversary of First HP Handheld Calculator", "Milestones:Development of the HP-35, the First Handheld Scientific Calculator, 1972", "HP Virtual Museum: Hewlett-Packard-35 handheld scientific calculator, 1972", CODEX 99 'The HP-35 Consumer Electronics, an Origin Story', The Museum of HP Calculators' article on the HP-35. The calculator used a traditional floating decimal display for numbers that could be displayed in that format, but automatically switched to scientific notation for other numbers. A clock rate of 200 KHz was sufficiently high to calculate a transcendental function within a second. would never sell because it was too expensive. The HP-35 and subsequent models have replaced the slide rule, used by generations of engineers and scientists.