conversations.from: human
conversations.value: Maria has a pen and a pencil. She bought the pen for half the price of the pencil. The pencil cost her $8. How much did Maria pay for both the pen and the pencil?
conversations.from: assistant
conversations.value: The pen is half the price of the pencil, so it's 8 * 0.5 = $4.
  So both the pen and the pencil cost Maria 8 + 4 = $12.