conversations.from: human
conversations.value: Jerome bought 5 new toy cars last month. This month he bought twice as many so that he has 40 toy cars now. How many toy cars did Jerome have originally?
  Solve this problem.
conversations.from: assistant
conversations.value: Jerome bought 5 x 2 = 10 toy cars this month.
  So he bought a total of 5 + 10 = 15 toy cars.
  Therefore, Jerome had 40 - 15 = 25 toy cars originally.