From what my professor told me, they were almost exclusively in their mid-20s, having just finished undergrad degrees in math. You're right — knowing if 1 is p

From what my professor told me, they were almost exclusively in their mid-20s, having just finished undergrad degrees in math. You're right — knowing if 1 is prime is kind of a trivial point, but this was a course for would-be math teachers specifically about how to teach _math_ to high schoolers. In fact, the specific context of the story was an in-class presentation about teaching kids about primes. I definitely should have mentioned that in the OP.