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The APF MARK 55 is a scientific calculator with 12 digits precision and RPN (reverse polish notation) logic. It has 45 functions, 30 keys and an LED (light-emitting diode) display, typical of calculators of this era. The power source is 3xAA sealed.

Facts at a glance:

Type Scientific
Functions 45
Keys 30
Precision 12
Logic RPN
Display type LED
Display size
Length 159 mm
Width 76 mm
Thickness unknown mm
Weight unknown g
Power Source 3xAA sealed
Original price unknown
Est. current value unknown
Year introduced 1977
Year discontinued

See other calculators manufactured by APF.