Uh Oh

According to Matthew L. Wald:

On the micro level, last weekend I watched a young cashier at the hardware store scan purchases and heard the customer complain that the total was wrong. I was terrified by the cashier's response. It wasn't, “No, the computer is right.” It wasn't, “let me double check.” It was, “How did you know?” When it comes to adding numbers in our heads, we've not only forgotten some skills, we've forgotten we ever had them.

ObSF: “A Feeling of Power” by Isaac Asimov.