When did people become unable to make change?
The bill at the taco joint was $26.71; Gunsmith Bob handed the (obviously new and overwhelmed) cashier a pair of twenties and, instead of punching in "four-zero-double zero-cash", she just hit "cash". This caused the drawer to pop open without the register displaying the amount of change she needed to make, and so she just stood there like a duck in thunder.
We'd be standing there still if I hadn't leaned forward and said "Thirteen dollars and twenty-nine cents."
I'm no math whiz. I can understand having trouble with quadratic equations or needing to grab a pad and pen for long division, but come on! This is basic arithmetic! This is third grade stuff!
Once upon a time I used to get upset when folks would slow the line down by using a debit card and therefore needing to punch in their PIN to buy a pack of gum, but these days that's usually much quicker than waiting for an innumerate cashier to laboriously count out the change from two bucks.