conversations.from: human
conversations.value: This math problem has got me stumped: Gemma ordered four pizzas at $10 each, and she gave a $5 tip to the delivery person. How much change did she get back if she gives one fifty-dollar bill?
  Can you show me the way?
conversations.from: assistant
conversations.value: The cost of the four pizzas is 4 x $10 = $40.
  The total cost, including the tip, is $40 + $5= $45.
  Therefore, Gemma gets a change of $50 - $45 = $5.