Uploaded November 2017 | Updated September 2026, 1 hour ago

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The Contex 10 was made by the Carlsen Brothers in Denmark from 1957 to 1971. About a million or them were made. In this video I show how to use this machine to do addition, subtraction, multiplication, and division.

For more information about this machine and other mechanical calculators in my collection, visit my website at jaapsch.net/mechcalc

0:00 Introduction, history
1:09 Description
1:41 Addition
2:26 Subtraction
3:32 Multiplication
5:13 Division
9:00 Outro