A slightly unhinged calculator fact: in the golden era of electronic calculators, some Japanese shopkeepers were reluctant to trust the newfangled tool, so Sharp made a line of combination calculator / abacus devices.
Here's a photo, next to some other stuff I own.
@lcamtuf (tries not to stroke pictures of gadgets)
Wow, those are super cool looking and historically interesting!
(Heart rate increases, desperately avoids eBay for the next week)
@lcamtuf There are many Soroban trainers out there to this day, including phone apps :) They take a lot of practice to use.
BTW, have you seen the Otis King cylindrical slide rule? They are very pretty - https://www.ebay.com/sch/i.html?_nkw=otis+king+cylidrical+slide+rule
@lcamtuf Βy the time I reached adulthood, mental arithmetic was no longer considered a necessary skill. Electronic calculators made it redundant.
But mental arithmetic is forever. Like riding a bike. Some of us have superpowers.
I have never seen those and now I'm browsing them on ebay, seem about US$50. Probably more than I want to spend on this novelty. But I was amused at this listing's description of a 9v.
@lcamtuf
They are in many smoke detectors, I'd hope they'd be a little familiar with them.
I do remember having a pair of Radio shack walkie talkies and constantly needing "transistor batteries"
The last I have purchased (over last ~12 years) all have non-replacable batteries. Only consumer electronics I have left using those is the garage door opener. Well *modern* consumer electronics. I do have a reel-to-reel tape recorder that takes C cells for motors and a "transistor" battery for the "six transistor" operation.
Given what calculators were like in that era, I wonder how many people noticed.
@lcamtuf I want one of these 🥺
(So that I can stop trusting calculators too, hehe)
lcamtuf 
Josh
dorian
Irrational Robot
Antacon
Lee Holmes 
Oblomov
plaes
wirepair
Mans R
Anthk
Flittermouse 🎸🥁🎹🏳️⚧️🐩
GJ Groothedde 🇪🇺
F4GRX Sébastien
Raymond Russell
Eli the Bearded
Asbestos
Michael K Johnson
Rusty Ring
Ben Pfaff
Avi 
🟣
itgrrl 
Hippo 🍉
Tim Chase
Kyle Rankin
David
Hey Gus
LordWoolamaloo
Colin