conversations.from: human
conversations.value: I'm completely lost with this math problem: Betty is saving money for a new wallet which costs $100. Betty has only half of the money she needs. Her parents decided to give her $15 for that purpose, and her grandparents twice as much as her parents. How much more money does Betty need to buy the wallet?
  Can you give me a hand?
conversations.from: assistant
conversations.value: In the beginning, Betty has only 100 / 2 = $50.
  Betty's grandparents gave her 15 * 2 = $30.
  This means, Betty needs 100 - 50 - 30 - 15 = $5 more.