Let’s talk a little about forgetfulness. I’m sorry, what was I saying? Oh, yes, forgetfulness.

The other day, I heard the first chords of that classic American sonata from the 1950s, Little Richard’s “You Keep A-Knocking, But You Can’t Come In,” and immediately sang along, remembering all the words perfectly. Granted, this wasn’t a major accomplishment, since the song only has about 11 words, and they are repeated multiple times. But still.

I can also recall, with no effort at all, the final lines of dialogue from the films “Casablanca,” “King Kong,” “Some Like It Hot” and “Invasion of the Body Snatchers” (original version, of course).

The lineup of the 1960 Yankees? Not a problem. George McGovern’s vice-presidential running mate? No sweat. Plus, I can tell you what the trigonometric functions are, from the mnemonic device that I learned in seventh grade trigonometry [*See footnote below if for some bizarre reason you really want to know or even if you have absolutely no idea what trigonometric means].

That is, then, that I have an excellent memory. World class, as long as we’re dealing here with my specialty of really unimportant and useless trivia from a long time ago.

So, here’s the question: How could I have left the house the other day and forgotten my wallet?

How could I have driven two thirds of the way to meet a friend for lunch before I realized that I had no wallet with me — no money, no credit cards, no driver’s license, no health insurance cards, nothing except the last line of “Invasion of the Body Snatchers” (original version) bouncing around in my head?

This is not, you understand, an isolated incident. On other occasions, I have forgotten my sunglasses, gotten into the car without my car keys, didn’t know where my cellphone was when my cell phone was in my pocket and walked into the kitchen to do something and then had no idea why I had walked into the kitchen, so I walked into the living room, and didn’t know what I was doing there, either.

I’ve also sometimes started sentences and forgotten how they were supposed to

Yes, I have considered the fact that I am just getting older and losing my mind. The problem is, I can’t remember where I lost it. My mind may still be in the car, but it’s possible it’s in the upstairs bathroom or with the cheese grater in the third drawer to the right of the kitchen sink.

But I’m not going to worry about it, though. In fact, I think I’ll just forget about it.

[The mnemonic device for you trigonometry fans: *It’s Soak Your Toe. That is, SOH-CAH-TOA, which stands for Sine equals Opposite over Hypoteneuse, Cosine equals Adjacent over Hypoteneuse and Tangent equals Opposite Over Adjacent. If you’re not a seventh-grader and understand what any of this means, or why I would remember it, submit your answer and you may win a prize — my seventh-grade trigonometry book, if I can recall where I put it.]