So yesterday, I tweeted this:

OMG America, please learn math.

— Professor O (@iswpw) September 4, 2016

Here’s the story behind that tweet:

Yesterday I went to Target and bought a few miscellaneous office supplies, because office supplies are good and cheap office supplies are even better. My order came to $3.32.

I handed the cashier a five dollar bill, and then remembering that I had a pocketful of change (I am officially in training to be an old man, apparently), I told the cashier that I had the two cents. I then fished around in my pocket for a moment, found two pennies, and handed them to her.

She looked at them as if I had placed a live baby duck in her hand. She honestly had no idea what I was doing. She looked at the “3.32” on her cash register screen, the two pennies in her hand and back at the screen. Then slowly, and with great deliberation, she typed “5.00” into her cash register screen, looked at the amount of change I was owed ($1.68), and then handed the two pennies back to me.

“You don’t need these,” she told me.

She then counted out my change to me—all one bill, two quarters, one dime, one nickel, and two pennies worth of it, as if I, or possibly her cash register, was trying to put one over on her. (Which wouldn’t surprise me, actually. I’ve worked retail and had training about the various ways that people can trick you out of a great deal of cash without your realizing what’s happening. If you want to see this in action, watch Paper Moon.)

I was reminded what a truly terrible job we do at teaching math in this country.

When I was in college, I worked at a place where even though our cash registers were capable of making change for us, we weren’t allowed to actually use that function. We had to figure out the change in our head, counting it back to the customer as we went. It actually prevented giving too much change back, because you count it back as you go instead of handing the customer a wad of bills.

In this case, she should have realized that by my giving her two cents, I was taking all the two pennies everywhere out of the equation. Instead of $3.32 and $5.00 we were actually dealing with $3.30 and $5.00. In the old days, I would have started counting up. I’d grab two dimes—that makes $3.50—and then two quarters—that makes $4.00. I would count that back to the customer, and then grab a one dollar bill, making $5.00 even.

But she didn’t have to make that kind of calculation in her head. All she needed to do was punch “5.02” into her cash register, and it would have told her to give me $1.70.

And yes, you can argue that she may have been unfamiliar with somebody giving her extra change in this way, or that she may have been wondering what kind of scam I was up to, or that she was new or tired or on cold medication and not thinking clearly. I won’t argue with that.

The thing of it is, though, that this kind of thing happens all the time. Once at McDonald’s my order came to $6.15 or something similar. I handed the cashier a twenty dollar bill, and he punched “20” into his cash register. I then remembered I had a quarter in my pocket and handed it to him. He tried to figure out how much change to give, grew confused, and then annoyed, and then upset, called his manager, who grew confused, and then annoyed, and then confident as he proceeded to give me $26.85 in change. So not only was I getting free food, I was being paid to eat it. I actually had to explain to the manager that in this case you just subtract the dollars and cents separately: $20 minus $6 equals $14, and 25¢ minus 15¢ equals 10¢.

The manager and cashier looked at me as if I were the practitioner of an ancient and eldritch art. In a way, I suppose I am.

Figuring that this was just a fluke, I tried it again a year later at a different McDonald’s. Same result. And not so long ago, I tried again, and guess what—yep, same result. It occurs to me that if we really wanted to, we could get free food at McDonald’s for the rest of our lives, or at least until McDonald’s goes bankrupt.*

This is not rocket science. This is basic arithmetic. The kind of stuff you learn in elementary school. And we suck at teaching it.

There are those (some of whom are in the elementary education business) who argue that we don’t really need to teach such skills, now that pocket calculators are easily and cheaply available. And yet in all these instances, these people had some very sophisticated calculators to hand. And they still flubbed it.

Make America great again? Heck, I’d settle for making America learn basic arithmetic again.

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