Monroe 98 Handheld Electronic Calculator

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A few makers of calculating machines survived into the era of electronic calculators. Monroe Calculating Machine Company, formed in New Jersey in the early twentieth century, initially made stepped drum calculating machines. A few years after it became a division of Litton Industries in 1958, the firm began to sell desktop electronic calculators. By the mid-1970s, it sold handheld electronic calculators as well. These were imported from Asia.
This handheld calculator has a tan plastic case and twenty-seven rectangular plastic keys. These include ten digit keys, a change sign key, a decimal point key, a total key, four arithmetic function keys, and four memory keys. In addition the device has a clear key, a squaring key, a square root key, a clear entry key, an inverse key, and a percentage key. The on/off switch is on the right of the top row of keys.
Text behind the keys reads: li MONROE 98 (/) Litton. Behind this is an eight-digit green fluorescent display. A jack for a power adapter is on the back edge.
The back of the case has four rubber feet. At the bottom is a battery compartment that would hold four batteries. A sticker on the back of the cover reads in part: CHARGING TIME 10-15 HOURS. A sticker above the compartment reads in part: MADE IN JAPAN FOR MONROE. It also reads in part: MODEL: 98 (/) SERIAL NO. F162199 (/) VOLTS 6 DC AMPS 0.05.
The calculator has a dark brown zippered case. A mark on the front reads: li MONROE (/) Litton The Calculator Company.
The case also holds a small pamphlet of instructions with title Monroe 98 Handbook of Operating Instructions. It is copyrighted 1976.
Currently not on view
date made
Litton Industries
place made
Physical Description
plastic (case; keys; carrying pouch material)
plastic (circuitry material)
paper (manual material)
overall: 1 1/2 in x 3 1/2 in x 6 in; 3.81 cm x 8.89 cm x 15.24 cm
ID Number
catalog number
accession number
Credit Line
Gift of John B. Priser
See more items in
Medicine and Science: Computers
Handheld Electronic Calculators
Computers & Business Machines
Data Source
National Museum of American History


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