>> I'd question why you'd ask an LLM something like this instead of Wolfram Alpha, or just look up the answer.
That's because OpenAI dedicated an entire section in claims that GPT-3 is reasonably good at arithmetic. See Section 3.9.1 titled "Arithmetic" in "Language Models are Few-Shot Learners":
https://arxiv.org/abs/2005.14165
Whence I quote below:
Overall, GPT-3 displays reasonable proficiency at moderately complex arithmetic in few-shot, one-shot, and even
zero-shot settings.
The reported results are pretty poor and too poor to justify even the relatively weak claim above (although the rest of the text in the same section very clearly and strongly implies that GPT-3 is doing something else than simply memorising a table of sums, which is an altogether much grander claim). OpenAI themselves seemed to be dubious enough about their own claim that the Arithmetic section of their paper was only included in the preprint (on Arxiv) and not in the published paper (in the 34th NeurIPS).
Yet, the claim in the preprint was still enough for people to forcefully argue that GPT-3 can do arithmetic, that it can learn the rules of arithmetic, and other impossible things before breakfast.
This is a discussion that goes back at least 3 years (judging from my comments where I point out that it's nonsense). It seems that the arithmetic ability of large language models is now a well accepted truth in the minds of the general public, who will casually use it to do, say, their maths coursework etc.
So blame OpenAI who made the big claims.