Entry-level trading position

Went through three rounds of interviews before getting a ding. Generally they ask you one or two personal questions to get you comfortable, then it's straight to brain teasers and mental math for the entire interview. Usually they end the question with something like "you have 10 seconds to answer." Questions consisted of long division in your head, brain teasers, and some probability stuff (Bayes, etc.) I would say they care about accuracy and timing, but you can earn yourself some points if you get something wrong by reasoning through and figuring out your mistake.