Amazon Operation Manager interview questions

Starts with the phone interview which takes about 30 minutes, then I had to wait a month and a half for them to get a hold of me for an onsite interview. There were 4 rounds of interviews. They were about 30 minutes. It seemed to me that they were rushing through the interviews because there were 8 of us all applying for the same job, which makes you feel uncomfortable while you wait for the next person to interview. The math question isn't difficult but why even have it??? They seem to management heavy they don't seem to care much about their hourly workers.