Monroe Model LA5-160 Calculating Machine

This compact full-keyboard electric non-printing and modified stepped drum calculating machine has a steel frame with rounded corners painted mottled dark green. The steel plate under the keyboard is painted light green. The eight columns of white plastic keys have nine keys in each column. Between the columns of keys, and under the green plate, are metal rods visible through windows in the plate. These serve as decimal markers.
To the right of the number keys are the subtraction and addition bars, two red buttons, one of which is marked R, and a red clearance key. Left of the keyboard is a lever with a red plastic top. In back of the keyboard is the carriage, with 16 result dials and eight revolution register dials. A crank with a wooden handle for clearing the carriage is on its right side and another one for shifting the carriage at the front. The machine has four rubber feet. A gray rubber electric cord plugs into the back, and a light gray cover fits over the object.
A mark on the front of the machine and on the cord reads: MONROE. A mark on the back reads: MONROE (/) REGISTERED TRADE MARK (/) HIGH SPEED ADDING CALCULATOR. The serial number, scratched on the underside of the carriage on the left, is 250245. The cover is marked: MONROE li.
This machine was used to keep the financial records of the Friends Meeting of Washington. Date deduced from serial number.
Compare MA*335424 and MA*334385.
Accession file.
National Office Machine Dealer’s Association, Blue Book, May, 1975, as compiled by Office Machine Americana, January, 2002.
Currently not on view
Object Name
calculating machine
date made
Monroe Calculating Machine Company
Physical Description
wood (overall material)
aluminum (overall material)
plastic (overall material)
steel (overall material)
rubber (overall material)
overall: 16.3 cm x 29 cm x 28 cm; 6 13/32 in x 11 13/32 in x 11 1/32 in
place made
United States: New York, New York
ID Number
catalog number
accession number
Science & Mathematics
Calculating Machines
See more items in
Medicine and Science: Mathematics
Calculating Machines
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of Friends Meeting of Washington

Visitor Comments

Add a comment about this object

**Please read before submitting the form**

Have a comment or question about this object to share with the community? Please use the form below. Selected comments will appear on this page and may receive a museum response (but we can't promise). Please note that we generally cannot answer questions about the history, rarity, or value of your personal artifacts.

Have a question about anything else, or would you prefer a personal response? Please visit our FAQ or contact page.

Personal information will not be shared or result in unsolicited e-mail. See our privacy policy.

Enter the characters shown in the image.