Uploaded November 2017 | Updated September 2026, 48 minutes ago

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These simple adding machines were made by the Carlsen Brothers in Denmark - model A from 1946 to 1950, model B from 1951 to 1970.

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

0:00 Introduction, history
0:51 Description
1:12 Clearing
1:28 Addition
2:29 No safety
3:41 Outro