Addimult Summator

[DA74254]

Going through my sister and I's late Parents house, we get to find different ends and odds.
I found my Dad's Addimult Summator. It does 9 digit addition and subtraction. I remember he showed me how to use it "a thousand years ago" and today I spent some time to (re)figure out how to work it. Yep, got it back into my fingers. It will go into my calculator collection and stay there until next generation takes over.