This is true. I asked a young school teacher to count out change one time.
Couldnt do it. Did not even have any idea what the hell I was talking about.
That would be funny, if it weren't so sad.
In order to try to keep sharp, I used to calculate my change in my head when I gave the cashier my money. Often, after using the "Amount Tendered" button and have the machine calculate the change they'd look at me and say, "How'd you do that"?
Another thing I used to do would be to make a comment about a historical event based on the amount due. For example, if the amount came to $19.41 I'd say, "That was a bad year". One day it came to $17.76 and I said, "That was good year". The cashier asked me what I meant, and I said, "You know, 1776; what happened in 1776; it was a good year". "Why is that?" she asked again and said she wasn't good with dates. I told her to never mind but asked her not to ever vote.