conversations.from: human
conversations.value: Solve the math problem: Last week, Charles bought a t-shirt for $30, a backpack for $10, and a blue cap for $5. The store gave him a discount and, in total, he only spent $43. How much of a discount did they give him, in dollars?
conversations.from: assistant
conversations.value: The purchases he made totaled $30 + $10 + $5 = $45
  He should pay $45, but he only paid $43, so $45 - $43 = $2 was the discount they gave him