There's no trick other than realizing it's not a prompt to guess. (And I have encountered this sort of question in interviews, although it went out of style bef

There's no trick other than realizing it's not a prompt to guess. (And I have encountered this sort of question in interviews, although it went out of style before you started interviewing 5 years ago.) It's amazing how many people will take a question like that and think the right thing to do is say "Um, 1000?" Or confidently nod and say "About 5500."