conversations.from: human
conversations.value: Find the answer to this math problem: There are 20 students in the class. Half of them play basketball. Two-fifths play volleyball and one-tenth play both basketball and volleyball.  How many students in this class do not play either game?
conversations.from: assistant
conversations.value: Half of the students are playing basketball, which means 20 / 2 = 10 students play basketball.
  Two-fifths plays volleyball, which leaves us with 20 * 2/5 = 8 students.
  One-tenth play both games, which means 20 * 1/10 = 2 students.
  There are 10 + 8 = 18 students who play basketball or volleyball.
  Among these 18 students, 2 of them are playing both games, so that means 18 - 2 = 16 students play only one of the two games.
  So finally, 20 - 16 = 4 students do not play either game.