I remember when ChatGPT first came out, I asked it for a proof for Fermat's Last Theorem, which it happily gave me.
It was fascinating, because it was doing a lot of understandable mistakes that 7th graders make. For example, I don't remember the surrounding context but it decided that you could break `sqrt(x^2 + y^2)` into `sqrt(x^2) + sqrt(y^2) => x + y`. It's interesting because it was one of those "ASSUME FALSE" proofs; if you can assume false, then mathematical proofs become considerably easier.
I remember that being true of early ChatGPT, but it's certainly not true anymore; GPT 4o and 5 have tagged along with me through all of MathAcademy MFII, MFIII, and MFML (this is roughly undergrad Calc 2 and then like half a stat class and 2/3rds of a linear algebra class) and I can't remember it getting anything wrong.
Presumably this is all a consequence of better tool call training and better math tool calls behind the scenes, but: they're really good at math stuff now, including checking my proofs (of course, the proof stuff I've had to do is extremely boring and nothing resembling actual science; I'm just saying, they don't make 7th-grader mistakes anymore.)
LLMs have improved so much the original ChatGPT isn't relevant.
My favorite early chatgpt math problem was "prove there exists infinitely many even primes" . Easy! Take a finite set of even primes, multiply them and add one to get a number with a new even prime factor.
Of course, it's gotten a bit better than this.