conversations.from: human
conversations.value: The teacher divided the students into four groups. One group had 5 students, another 8 students, and the third 7 students. If there were 24 total students, how many students were in the fourth group?
  Work out the solution step by step.
conversations.from: assistant
conversations.value: There are 5+8+7=20 students in the first three groups.
  There are 24-20=4 students in the fourth group.