[vundercind]

Yikes. I mean, on the one hand that’s literally elementary—as in elementary school, if only just barely—knowledge. On the other, I’ve not needed to find the circumference of a circle given the radius ever in adult life, and I’m quite sure I’ve forgotten more than a handful of “elementary” things due to lack of practice, over the years, especially in math (for which needing to reach for knowledge or techniques beyond about 6th grade is very rare, at least in my life).

… I am pretty sure I’d be fine on that particular example, but there are surely others about as “easy” that I’d flub because I’ve not used that knowledge in 20+ years.