Die Curta ist eine mechanische Rechenmaschine in Form eines Zylinders mit einer Kurbel an der Oberseite. Das Funktionsprinzip ist das der doppelten Staffelwalze. Sie wurde in den 1940er Jahren von Curt Herzstark entwickelt

Philipp Matthäus Hahn – Wikipedia

maximusrex23 – Flickr

electropod – Flickr

Bild: electropod

Monroe High Speed Adding Calculator

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

Chadwick – Magic Brain Calculator

The Magic Brain Calculator was a device used many years ago (mabye 1950's) to solve maths problems. It requires you reset it to all zero's to begin with and after a bit of practise you can solve many types of mathematical calculations. Clearing the device is just a matter of pulling the metal bar at the top of the machine and pushing it back in. Calculations of up to 8 digits can be performed such as addition, subtraction and multiplication.
Bild: marsmet552

Wilhelm Schickard (* 22. April 1592 in Herrenberg; † 23. Oktober 1635 in Tübingen) war ein deutscher Astronom und Mathematiker.