making change

I paid cash for my lunch at the grocery store the other day. Didn’t expect the high school guy at the register to count back my change the way cashiers used to, but I did expect him to be able to add up the values of the coins as he was making change, which he was apparently having a lot of trouble with. He started by digging out a couple of quarters, which he obviously added up in his head, then thought long and hard about whether to grab another quarter, decided not to, dug a couple of dimes out of the till and mentally added them to the quarters, then stared at the display while trying to decide how many nickels he needed. It won’t be too much longer until the register displays the change graphically: dollar bill, dollar bill, dollar bill, quarter, quarter, dime, nickel, penny, penny.