Last Saturday I ordered a pizza over the phone. When I went to pick it up a young guy, looking to be about 17, waited on me and told me my order came to $16.61. I dug out the 61 cents and handed it over, and having a wad of bills in my wallet that I wanted to reduce, I gave him a five and a one. Then I gave him a twenty (I didn't have a ten or any more fives). He looked at it a moment and then looked at me rather quizzically, as if needing an explanation. I told him that I had just gave him $26.61 and would like ten dollars back. This didn't register at all. So I told him exactly what I had just done, that the bill was $16.61 and the total amount of money I had given him was $26.61 and that 16.61 from 26.61 was 10. He was still drawing a blank, and after a moment called one of the other workers to come over and take a look at what was happening. She immediately saw the situation and told him to give me $10.00. Almost reluctantly he handed over my $10.00. What was interesting is that here was what I assume to be a high school senior---perhaps a junior---who was intelligent looking enough, but unable to do simple math in his head. I know there are a number of people out there who are in the same boat, but I had never come across one before.
Ever have one of these encounters?