HP-80

The HP-80 was HP's second handheld calculator. This calculator was designed for business rather than scientific/engineering. In addition to having different functions, it was designed with a different philosophy. Whereas the HP-35 was designed for technical/mathematical users, the HP-80 was designed to be a problem solver that didn't require its users to know the formulas needed. Thus, the user could simply enter the parameters of a business problem and get an answer with a single keystroke. (In other words, the HP-35 user supplied the formulas, but on the HP-80, the calculator supplied them.)