I would like to see a calculator made out of pixie tubes too It looks like those are high voltage like nixie tubes. I bet you could you make modern pixie tubes with some LEDs.

David Anders is on a mission to make a modern version of the Harwell Dekatron machine aka the WITCH using very many LED modules which act as Dekatrons (a gas discharge counting tube perhaps like a pixie)
https://hackaday.com/?s=Dekatron+
https://hackaday.com/2012/11/20/worlds- ... -exchange/

I don't know where the VFD displays started being called Nixies.
They work quite differently and require different voltages.
People selling VFDs are always adding the words Nixie but that doesn't
make them Nixies.
I don't think I've ever seen a Dekatron with numbers before but I see
no reason it couldn't be.
They are not particularly good for calculators since they are primarily self counters and not random displays.
Dwight

That sounds even cooler. It would look really old fashioned to watch them all count up to the right number when you calculate. Do they have a reset line?

Yes
Dwight