[tkgally]

I don't, but I sometimes see them used here in Japan. Some small-shop operators use them to add up charges and show the total to the customer. I was recently in the office of a small company, and I noticed that the bookkeeper had a calculator next to a pile of paper (receipts?) on her desk. She also had a computer in front of her with a spreadsheet on the screen.

When I moved here forty-three years ago, it was common to see abacuses used in similar situations. There's still an abacus school [1] not far from where I live, but it's been a long time since I saw one in use.

[1] https://maps.app.goo.gl/nvTg4hfSjTcba47c8

[Froedlich]

Back in the (early 1960s?) Isaac Asimov wrote a book on how to do arithmetic calculations in your head. He pointed out that someone who developed that skill could solve problems faster in their head than by reaching for a slide rule, and they wouldn't necessarily be limited to slide rule approximations. Engineers, accountants, etc. would be more productive by being able to do calculations without having to reach for a slide rule or pencil and paper.

[pause for 'slide rule' chuckle]

The same applies to "open calculator app and key the figures in," though. I'm not sure that "user interface" was a thing back when he wrote that, but that's what he was talking about.

[tkgally]

That’s one reason the abacus hasn’t been completely replaced by calculators: some abacus users become able to calculate very quickly in their heads by visualizing the changing bead positions. In Japanese the skill is called 暗算 anzan, literally “dark calculation.”

[JohnFen]

> There's still an abacus school

(I'm in the US) I remember being taught how to use an abacus when I was in grade school. Not kidding. I'm not so old that they were used anywhere in real life. I believe the whole point was to teach different ways that calculating can be done. A little horizon expansion.