conversations.from: human
conversations.value: Jimmy bought 3 pens for school for $1 each, 4 notebooks for $3 each and 2 folders for $5 each. If he paid with a $50 bill, how much change will he get back?
  How to solve this?
conversations.from: assistant
conversations.value: Jimmy spent 3 * $1 = $3 on pens.
  He spent 4 * $3 = $12 on notebooks.
  He spent 2 * $5 = $10 on folders.
  He spent $3 + $12 + $10 = $25 in total.
  His change will be $50 - $25 = $25.