You just can't fix "stupid".Sad but true. Even with the cash register showing what the change should be, many times I've seen cashiers hesitate when giving change. Seriously. When I decided to retire, in training any individuals (yes, it was plural b'cuz most of them simply couldn't get the concept of what the job entailed & had to be let go) I realized that I thought I was bad at math - hell, I'm a genius based on what I saw. They couldn't understand percentages, pro-rating etc. It was extremely disturbing and I wondered what these kids are being taught in school. Needless to say, my former employer is STILL trying to fill the position as I wasn't willing to stay any longer on the job. I did manage to train one person but she didn't last long - apparently the "work load" was too much to handle. Gez, I did it for 18 years! Guess work is the last thing they actually want to do. Not all are like this but the ones I interacted with were.
Now that apparently there's a "new math" and that 2+2 doesn't necessarily = 4, the future of engineers that I'm seeing will mean bridges, roads & tunnels falling apart because the math just doesn't work.