## Someone Else’s Homework: A Postscript

My friend aced the mathematics final. Not due to my intervention, I’d say; my friend only remembered one question on the exam being much like anything we had discussed recently. Though it was very like one of those, a question about the probability of putting together a committee with none, one, two, or more than two members of particular subgroups. And that one we didn’t even work through; I just confirmed my friend’s guess about what calculation to do. Which is good since that particular calculation is a tedious one that I didn’t want to do. No, my friend aced it by working steadily through the whole term. And yes, asking me for tutoring a couple times, but that’s all right. Small, steady work adds up, in mathematics as with so much else.

Meanwhile may I draw your attention over to my humor blog where last night I posted a bit of silliness about number divisibility. Because I can’t help myself, it does include a “quick” test for whether a number could be divided by 21. It’s in the same spirit as tests for whether a number can be divided by 3 or 9 (add the digits add see whether that sum’s divisible by 3 or 9) or 11 (add or subtract digits, in alternate form, and see whether that sum is divisible by 11). The process I give is correct, which is not to say that anyone would ever use it. Even if they did they’d be better off testing for divisibility by both 3 and 7. And I don’t think I’d use an add-the-digits scheme for 7 either.

## Reading the Comics, March 3, 2016: Let Popeye Do Mathematics Edition

Elzie Segar’s Thimble Theater is a comic strip you maybe vaguely remember hearing about for some reason. The reason is that, ten years into its run, Segar discovered a charismatic sailor named Popeye. People who read my humor blog know I’m a bit Popeye-mad, even still. Comics Kingdom has in its Vintage comics run the strips from the first story where Popeye appeared. This isn’t it. That story resolved, and the comic tried to carry on with the old cast. It didn’t last. After a few dull weeks Segar started making excuses to put Popeye back on-screen. It’s quite like Dickens’s Pickwick Papers and the discovery of Sam Weller, right down to this being the character that made the author famous.

As part of Segar’s excuses to keep Popeye on panel, nominal lead Castor Oyl has hired a tutor. It’s not going well. I blame the tutor, who’s berating Popeye for being wrong and giving no hint what to do right. But in this installment, originally run the 14th of September, 1929, we get around to arithmetic. Popeye is either a natural, has experience we don’t know about, or is quite lucky. It wouldn’t be absurd for Popeye to be good at some kinds of arithmetic. If he’s trained in navigation he’d probably pick up a good bit of practice calculating. I don’t know anything but the most trivial points of how to calculate one’s position at sea. So I can’t say if it’s plausible Popeye would have practiced calculations like “six and a half times 656”. He may just be lucky.

Mark Litzler’s Joe Vanilla for the 26th of February was the anthropomorphized numerals joke for this go-round.

Mark Tatulli’s Lio for the 26th features soap bubbles made into geometry diagrams. I like that; it’s cute. Coincidentally, Guy Gilchrist’s Nancy for the 29th turns the pieces of a geometry puzzle into pizza. I think that’s a lesser version of the joke. It’s less absurd.

Nick Seluk’s The Awkard Yeti for the 2nd of March is a Schrödinger’s Cat reference alongside a butterfly reference. It seems Comic Strip Master Command challenges my “I’ve said all I can say, for now, about Schrödinger’s Cat and Chaos Butterflies” policy.

Missy Meyer’s Holiday Dodles mentions the 2nd of March was World Maths Day. I hadn’t heard about this; had you? Wikipedia indicates it’s a worldwide mathematics competition event sponsored by 3P Learning. Also that the first one was held on “Pi Day”, the 14th of March, which would make sense. I didn’t know it was Dr Seuss’s birthday either until I ran across a third comic strip doing some Dr Seuss jokes. Comic strips sometimes line up by accident. But I’m always impressed when they spontaneously (I assume) line up for some minor event like that.

Charles Schulz’s Peanuts for the 3rd of March originally ran the 6th of March, 1969. It’s part of a storyline in which Linus’s favorite teacher, Miss Othmar, is replaced following a teacher’s strike. This is why he complains to the new teacher about how Miss Othmar never did things that way.

It gets to appear here because Linus suggests that for some problem or other “we could divide instead of subtract”. I’m a little curious what the problem might have been. Division is often presented as a sort of hurried-up subtraction, or at least it was when I was Linus’s age. But they don’t quite address the same sorts of questions. I suppose something like “how many times eight goes into thirty-two”. But I wouldn’t do that by subtraction except to point out how division answers that question so much better. Still, there is a good point in showing how there can be several ways to do a problem. There almost always are. Sometimes a particular approach is faster than another. Sometimes it’s less confusing than another. Sometimes it gives better insight into other problems than another. If all you are interested in is the right answer, then you can use whatever method works, including letting Popeye guess for you. But, except on the frontier of research where we don’t quite know what we’re studying, there are always choices in how to find an answer.

Tom Toles’s Randolph Itch, 2 am for the 3rd I feel confident I’ve shown before. The strip didn’t run long originally and it’s in its third or fourth rerun cycle on Gocomics.com. It’s still an amusing bit of figure drawing, drawn by figures, being figured out. I make it out to 111,193.

Dave Whamond’s Reality Check for the 3rd of March is a little too proud of knowing some common mathematical symbols.