I was recently in a line at the store where a person paid using cash, a rare thing these days. The Cashier, mid 20's person, could not even tabulate the total amount handed to them in their mind to enter that total in the computer to get the change amount. Ended up handing it back to the customer using "how much is there"

I wept for the state of public education, basic addition is lost skill it seems

> I wept for the state of public education, basic addition is lost skill it seems

What does this have to do with "public education"?

They could have been taught it in elementary school, but if they were in their mid-20s, then it would probably have been over a decade since they were tested on it even in secondary/high school.

And that skill would have atrophied with non-use on a day-to-day basis.

basic addition is not a skill that atrophies. We are talking the most basic math there is, adding whole numbers. 1+1 = 2, or in this case 50+20+1+1+1+5 = 78

> basic addition is not a skill that atrophies.

The evidence you provided suggests otherwise. :)

I'm sure the person can still add, but it's a bit slow(er) without practice, they got frustrated, and so handed back the change.

But when do people need to do more than a handful of mental calculations? While you might be faster with a mental abacus than with a calculator, I doubt that you beat an Excel spreadsheet. If Excel is unavailable for some reason either the source data you would need is unavailable too, or your mental calculation speed is not fast enough to be useful, even with the mental abacus.