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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 RPN (reverse polish notation) 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 NiCd pack.

Facts at a glance:

FeatureValue
TypeProgrammable
Functions75
Keys35
Precision12
LogicRPN
Display typeLED
Length147mm
Width81mm
Thickness33mm
Weight255g
Power Source3xAA NiCd pack
Year introduced1975
Year discontinued1977

Replacements:

If you have a Hewlett-Packard HP 55 that is no longer working, you can first try replacing the 3xAA NiCd pack batteries. If that doesn't solve the problem, then you can consider replacing the calculator with a modern equivalent.

We suggest the following current model as a replacement:

See other calculators by Hewlett-Packard