Monroe High Speed Adding Calculator
![](https://it-spots.de/wp-content/uploads/2012/05/379006423_783057504d_z-360x259.jpg)
Monroe Adding Calculator from Colorado. Motor attached on left side. Column zero buttons are in red. Left-right shift crank in front, Counter and sum reset crank on right. (High Speed is relative - multiplication takes a few seconds). There is a manual override knob on the right side (not pictured) for advancing or resetting in case it gets stuck mid-calculation. 1922-
Bild: egcd32