Amazon Operation Manager interview questions

I was contacted by a recruiter, who scheduled a phone interview, which involved several behavioral questions and a math question. Two days later, I was invited to participate in on-site interviews. All expenses were covered. The onsite interviews consisted of four interviews, three with operations/senior operations managers and one with an HR manager. Candidates were also asked about a written sample they had provided earlier and another math question, which they complete before interviews begin. The interviewers were courteous and helpful and the atmosphere non-threatening. There were several candidates going through interviews at the same time, but all interviews were conducted on-on-one.

Phone interview was not difficult but the manager who interviewed is big on managerial/supervisory question. I didn't have a lot experience doing supervisory tasks. My experience is handling/managing operation and working with a team and not as a direct manager. Math question is easy, same question posted here.