And I'm wrong; it's a reprint that shows us that Mike tends to tune people out.
Panel 1: As Elly puts Mike's jacket on him, she tells him that Miss Campbell said that his number work is fine but that he needs help with his printing.
Panel 2: Elly then goes on to tell him that she did say that he has trouble listening; she tells him that he doesn't listen and listening is very important.
Panel 3: She then says "You can't learn if you can't listen, can you, honey?"
Panel 4: His baffled response of "HUH??" leaves her gobsmacked.
Summary: Back in 1981 when I first saw this, I had wondered if Mike might have needed his hearing tested; that's because I was sixteen and didn't realize that he'd never been in an environment where listening was valued. John doesn't listen to Elly, Elly doesn't listen to anyone and no one listens to him so he went with the flow and tuned Miss Campbell out. Another reason that this strip stinks on ice is that his mother is a fine one to talk when it comes to focusing in class; she never completed her university education because she couldn't be bothered paying attention to her teachers so her lecturing Mike is the rankest hypocrisy.