HP calculators

The HP-35 was Hewlett-Packard's first pocket calculator and the world's first scientific pocket calculator: a calculator with trigonometric and exponential functions. It was introduced in 1972.

programming language

The HP-32S (codenamed "Leonardo") was a programmable reverse Polish notation scientific calculator introduced by Hewlett-Packard in 1987. It was succeeded by the HP-32SII scientific calculator.

The HP-42S RPN Scientific is a programmable RPN Scientific hand held calculator introduced by Hewlett-Packard in 1988. It is a popular calculator designed for science and engineering students.

series of graphing calculators produced by Hewlett-Packard

family programmable calculators and desktop computers

The HP-22S is an electronic calculator from the Hewlett-Packard company which is algebraic and scientific. This calculator is comparable to the HP-32S. A solver was included instead of programming. It had the same constraints as the 32S, lacking enough RAM for serious use. Functions available include TVM and unit conversions. Only single letter variable names are allowed. Marketed as a student calculator, the 22S uses infix notation rather than the reverse polish notation used on some higher-end HP calculators of the same era.

thumb|right|Hewlett-Packard HP-01 watch displaying the time

Graphing calculator by Hewlett-Packard