Every spring, our family goes to Maryland Day, the annual celebration on the campus of the University of Maryland. One one occasion a few years ago, I took my kids up to a pizza booth to get some lunch. Pepperoni slices were $4.50 and cheese slices were $4.00. I ordered 2 pepperoni slices and 1 cheese slice, which came to a total of:

$4.50 + $4.50 + $4.00 = $13.00

The woman in the booth, whom I estimated to be in her mid to late 20s, said, “$15, please.”

I asked, “How do you come up with $15?”

She replied, “2 times $4.50 is $9.00,” (correct so far), “plus $4 makes $15.”

I replied, “Sorry, but $9 + $4 = $13, not $15.”

She insisted that it was $15, and we went back and forth a few times on this.

Fortunately, I had exact change, and I handed her $13. I said, “Ma’am, it comes to $13, and here you are. Feel free to check with any of your colleagues. Have a nice day.”

Experiences like this are among the reasons that math is a subject that is near and dear to my heart.

I’m not asking for integral calculus or a proof of Fermat’s Last Theorem. But I don’t think it’s too much to ask somebody at a pizza booth to perform basic arithmetic, especially when the numbers have dollar signs in front of them and when my money is involved in the transaction.

CobeShe was including her tip.

John McCloskeyPost authorI am quite a generous tipper when the service justifies it. This case did not qualify.