Hewlett-Packard HP 55 (Classic MERLIN)

Hewlett-Packard HP 55
Image: Wikimedia CC BY-SA 3.0
The Hewlett-Packard HP 55 is a programmable calculator with 12 digits precision and algebraic logic. It has 75 functions, 35 keys, and an LED (light-emitting diode) display, typical of calculators of this era. The power source is 3xAA.

Facts at a glance:

Feature Value
Type: Programmable
Functions: 75
Keys: 35
Precision: 12
Logic: Algebraic
Display type: LED
Length: 147mm
Width: 81mm
Thickness: 33mm
Weight: 255g
Power Source: 3xAA
Year introduced: 1975
YearDiscontinued: 1977

See other calculators by Hewlett-Packard