ObviouslyNotBanana

That's pretty sigma

Well I did that manually and it sure does work out to 125. Wonder why it doesn't work with the functions the calculator is supposed to have. Thanks for the patience lmao

I guess that's why I don't know what I'm looking at. I've not had great math teachers through my school time, and I don't actually know what this is supposed to do. Like, in actual math steps.

I see that the result should be 125. Why ain't it 120?

That shows 120.

I wish I did but I ate a slice

I can say that A seems to be Auto in the way you think but I haven't figured out what criteria it has for this automation. Maybe there's a way I could figure it out. I'm not a maths kind of guy (had pretty bad teachers in school) so it's all honestly above my head. Shamefully enough.

If I switch the power on, and press the IC key nothing happens. But I do, as far as I can see, any calculation and press IC I get a (to me) random number displayed on screen. So yeah, that might be the case but I'm not sure what items it is counting. The RV key seems to flip between different numbers.

Impact Calculation might just be a mistranslation. DeepL seems to think it should be mark-up. Following what you told me, I still get no result from operating the calculator with MU and %. Which is surprising me because it acts like those keys have no function.

I'll write it in the order I press the keys and maybe you'll figure out what I'm doing wrong.

Switch on > 100 > MU > 20 > % = 20

It displays 20 even if I press += after. The display does update, so it is registering the key presses at least.

¯\_(ツ)_/¯

edit: ok I think I figured it out. It's MU > 100 > X > 20 > % > += > 120

Yeah, that makes sense, though the calculator doesn't have a printer unless by print you mean something I'm too much of a scrub to understand!

The MU button doesn't "do" anything by itself. You'll need to press 100. Press MU. press 20. Press %. Or maybe the sequence is different. It would be nice with a manual.

Yeah I tried doing these things in different orders but they don't seem to affect one another in any way. Maybe it needs one of the switches in a certain spot or something.

A manual would definitely be a nice thing. Sadly I haven't been able to find one.

Actually I found this site (in German) which says that the MU is for Impact Calculation. Which... I wouldn't even begin to try to understand how I'd use.

Right! I haven't even thought about when yet.

All I can tell you is that the right side is somehow related to the rightmost switch. C and CE do what they do on any calculator.

That's some great info!

The back of it says it's been used at a local insurance company. Wonder if that button is useful there somehow.

Do you know what the rightmost row is about? And the two buttons above C and CE?

edit: the MU function doesn't seem to do anything. Maybe I'm missing something.

True.