conversations.from: human
conversations.value: This math problem has got me stumped: Liam and Mitchell own competing lemonade stands across the street from one another. When Liam bragged that he had made $63 one weekend, Mitchell laughed and told Liam he had sold 21 lemonades at $4 apiece the same weekend. How many more dollars did Mitchell make selling lemonade that weekend than Liam?
  Can you show me the way?
conversations.from: assistant
conversations.value: Mitchell made 21 * 4 = $84 selling lemonade.
  Thus, Mitchell made 84 - 63 = $21 more selling lemonade that weekend than Liam.