conversations.from: human
conversations.value: I need help with this problem:
  Paul went to a shop to buy some groceries. He bought some bread for $2, butter for $3, and juice for two times the price of the bread. He had $15 for his shopping. How much money did Paul have left?
conversations.from: assistant
conversations.value: The price of the juice was 2 * 2 = $4.
  So in total he paid for his shopping 2 + 3 + 4 = $9.
  That means he had 15 - 9 = $6 left.