A few years ago, I remember concerns that teaching children math with calculators would leave students unable to do arithmetic without them. I think a bigger problem is people who can’t even handle simple subtraction with the calculator.
I had another fun encounter with a retail employee today. I stopped at Subway on the way home. After semi-competently putting together my order, he punched some buttons on the register and undercharged me by about two dollars. I pointed this out, at which point he got confused and called over the other employee (I think he was new), who entered the correct information into the register.
After exchanging some bills, there was still the fractional part of my bill—12¢—left to settle. He opened the cash drawer and stared at it for a while. At the suggestion of the other employee, he tried the calculator, with little success. I helpfully suggested that the change was 88 cents, but this apparently confused him more. He mumbled something about being “bad at math,” told the register I had tendered exact change, took three quarters out of the drawer and closed it. He then took another quarter out of his own pocket and gave me whole a dollar in change.
Both the calculator and the register would have given him the right change, if he’d been at all competent at using them. I tried to tell him the answer, but apparently converting “eighty-eight cents” into three quarters, three pennies, and a dime is too difficult a problem.