conversations.from: human
conversations.value: Randy has $30. He spent $10 buying his lunch. He spent a quarter of the money he had left on an ice cream cone. What is the amount of money, in dollars, Randy has left?
conversations.from: assistant
conversations.value: Randy has 30-10=20 dollars left after buying lunch.
  Randy spent 20/4=5 dollars on the ice cream cone.
  Randy has 20-5=15 dollars left.