If you hand a broken calculator to someone who knows how to do math, and they entered 123 + 765 which produced an answer of 6789; they should instantly know something is wrong. Hand that calculator to someone who never understood what the tool actually did but just accepted whatever answer appeared; and they would likely think the answer was totally reasonable.

Catching an LLM hallucinating often takes a basic understanding of what the answer should look like before asking the question.

One time when I was a kid I was playing with my older sister's graphing calculator. I had accidentally pressed the base button and now was in hex mode. I did some benign calculation like 10+10 and got 14. I believed it!

I went to school the next day and told my teacher that the calculator says that 10+10 is 14, so why does she say it's 20?

So she showed me on her calculator. She pressed the hex button and explained why it was 14.

I think a major problem with people's usage of LLMs is that they stop at 10+10=14. They don't question it or ask someone (even the LLM) to explain the answer.