Monroe Model LA5-160 Calculating Machine

This full-keyboard electric non-printing stepped drum calculating machine has a metal frame painted black, with the plate under the keyboard painted green. The eight columns of white and tan plastic number keys have nine keys in each column. Below each column is a tenth white key used for zeroing. Between the columns of keys, and under the green plate, are metal rods visible through windows in the plate which serve as decimal markers.
To the right of the number keys are the subtraction and addition bars, a red button, and a red clearance key. Left of the keyboard is a lever. In back of the keyboard is the carriage, with 16 result dials and eight revolution register dials. The revolution register dials have the digits 1 to 9 in red and 0 to 9 in black. There is a crank for clearing the registers on the carriage on its right side and another one for shifting the carriage at the front. The machine has four rubber feet.
A mark on the front of the object reads: Monroe. A tag on the right side reads: LA5-160 (/) 472869
Compare MA.335424 and MA.335235. The Monroe LA5-160 was introduced in 1932.
Business Equipment Topics, vol. 81, July, 1932, p. 14, 16.
National Office Machine Dealer’s Association, Blue Book, May, 1975, as compiled by Office Machine Americana, January, 2002.
Monroe Calculating Machine Company, “Monroe High Speed Adding-Calculator,” Publication 780-A. This is a notebook with advertising descriptions of several Monroe calculating machines.
Business Equipment Topics, vol. 81, July, 1932, p. 14, 16.
Currently not on view
date made
Monroe Calculating Machine Company
Physical Description
steel (overall material)
rubber (overall material)
plastic (overall material)
overall: 16.5 cm x 29 cm x 28.5 cm; 6 1/2 in x 11 13/32 in x 11 7/32 in
ID Number
catalog number
maker number
LA5-160 472869
accession number
Credit Line
Gift of Richard G. Freeze
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Calculating Machines
Data Source
National Museum of American History


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