[BeetleB]

It's a workplace situation, and I think it's appropriate to say:

"I've asked four times what 2+2 is, and you've told me several stories about addition but haven't answered the question. Is there some reason you're not able to tell me what 2+2 is?"

In a party, perhaps not.

I've often phrased it as:

"I've asked four times what 2+2 is, and I still don't have an answer to that question. I'm afraid I cannot proceed with X until I know the answer to that question."

Often, though, I've found that simply putting the burden on the other party unblocks them. It shifts their mindset from "I need to answer a question" (which they think they did) to "I need to solve this problem" (which they realize they haven't).

"We need X. Can you sort it out?"