conversations.from: human
conversations.value: Each class uses 200 sheets of paper per day. The school uses a total of 9000 sheets of paper every week. If there are 5 days of school days, how many classes are there in the school?
  Can you solve this problem?
conversations.from: assistant
conversations.value: Each class uses 200 x 5 = 1000 sheets of paper in a week.
  Thus, there are 9000/1000 = 9 classes in the school.