I was putting things in order in a garage, when I found an arithmometer Felix M. It is old school iron gadget, there are no electronics inside.
Ages ago, my father used to work as an engineer. He had used a student slide rule & a piece of sheet for calculating, so, he bought an arithmometer Felix M in 1978 for increasing calculation speed. It was the decline of the arithmometers. On one hand, it was possible to buy an Elektronika B3-18A, but on the other hand, a price was stratospheric, The price was 220rub, but an engineer salary was about 120-140rub. However, an arithmometer price was 15rub. An arithmometer price was winning argument & my father bought it. Interesting fact: the Felix M is a great traveller. It was bought in Cherepovets, moved to from Vladivostok to Baikonur, stayed in Chelyabinsk and finally moved to Saint Petersburg.
The arithmometer weight is about 5kg. It was stored in a garage about 20-25 years. As a result, doesn’t look really good, however, it works fine.
How does it work? I’ve prepared the video. Let’s multiply 11 by 321: