The Hewlett-Packard Company, commonly shortened to Hewlett–Packard or HP, was an American multinational information technology company headquartered in Palo Alto, California, that developed and provided a wide variety of hardware components as well as software and related services to consumers, small and medium-sized businesses (SMBs) and large enterprises, including customers in the government, health and education sectors.

The company was founded in a one-car garage in Palo Alto, California by Bill Hewlett and David Packard in 1939, and initially produced a line of electronic test and measurement equipment. 

They introduced the world's first handheld scientific electronic calculator in 1972 (the HP-35). It is a calculator with trigonometric and exponential functions.

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 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. 

The fifteen-digit LED display was capable of displaying a ten-digit mantissa plus its sign and a decimal point and a two-digit exponent plus its sign. 

The display used a unique form of multiplexing, illuminating a single LED segment at a time rather than a single LED digit, because HP research had shown that this method was perceived by the human eye as brighter for equivalent power. 

According to en.wikipedia