Caleb Shor
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cshor.org
Caleb Shor
@cshor.org
* Math professor at WNEU
* Director of PROMYS for Teachers at Boston University
* Travel enthusiast
* Fan of lists
Gracias.

I’m toying with the idea a problem set about dissecting squares into triangles for the next workshop. Thoughts? I can hold off, esp if you could attend somehow (in person or zoom) next semester.
October 19, 2025 at 11:07 PM
May 25, 2025 at 7:13 PM
FWIW, I just typed this prompt into math-gpt.org and it answered the question correctly.

(There appear to be a few math gpt websites. That’s the first one that appeared when I searched.)
May 25, 2025 at 7:06 PM
Looks to me like you negated both the numerator and denominator (instead of just one of them) in the very last step. Otherwise I buy it.
May 19, 2025 at 9:36 PM
Wow, this is a disaster.
March 26, 2025 at 9:55 PM
Thank you for sharing tonight! And on such short notice. Always great to see you. I like the way your brain works.
March 13, 2025 at 2:29 AM
I like this approach! As I read it I was going to mention that it’s in the pcmi materials. And then I finished reading what you wrote. Ha!
March 13, 2025 at 2:26 AM
Hadn’t seen that! Thank you for sharing it. You have some really great MO posts.
March 1, 2025 at 2:55 AM
The problem is quite doable without any knowledge of Legendre symbols btw.

and sending you stuff is on my to do list.
February 28, 2025 at 9:58 PM
Ha. That was a fun read. There’s actually a lot of good stuff in there. A lot of handwaving too — not sure it’s providing a ton of insight. The key is why that sum of (n/p) * ((n+1)/p) is -1, which it dodges explaining. I’m not sure that’s a “well-known result” as is claimed.
February 28, 2025 at 7:16 PM
I like it!
February 27, 2025 at 3:49 AM
Err, squares mod p. Blah.
February 26, 2025 at 4:02 AM
I like the quiz very much.

And I will share materials. Seriously. Previously I had the excuse that I was traveling. Now I’m not. But my computer is waaaay over there.

Here’s a problem I saw recently. For p prime, how many integers n in {0,1,…,p-1} have the property that n and n+1 are both squares?
February 26, 2025 at 3:41 AM
I really like that fact about n dividing a number that’s all 9s! It’s a good one. I often put that on the final exam when I teach number theory.
February 26, 2025 at 3:32 AM
Pretty sure! Otherwise the whole state would be shut down and we’d be open. (Kind of like on Presidents’ Day.)
February 18, 2025 at 2:29 PM
Or sin x / n = six.
February 18, 2025 at 4:37 AM
That seems reasonable. Are your students using it as well?
February 15, 2025 at 5:45 AM
I haven’t seen any compelling reason to like it for the math I teach or do.

The main thing I’ve seen is students using it to pass off its “work” as their own. Maybe it’s good for certain subjects, but eg AI-produced proofs in an abstract algebra course are hot garbage.
February 15, 2025 at 1:32 AM
I see a second player win. Player 2 (P2) selects the same 4 rows as player 1 (P1). Call those rows A, B, C, D.

If P1 makes a move in one of rows A and B, P2 makes the same move in the other row. Same idea for rows C and D.

This way, whenever P1 has a valid move, P2 does too. Fun!
February 11, 2025 at 5:28 PM
This was fun. The extra helpful part at the end made me laugh!
February 2, 2025 at 10:16 PM