conversations.from: human
conversations.value: Yanna bought ten shirts at $5 each and three pairs of sandals at $3 each.  How much change did she get back if she gave a one hundred dollar bill?
  How to solve this?
conversations.from: assistant
conversations.value: Ten shirts cost 10 x $5 = $50.
  And, three pairs of sandals cost 3 x $3 = $9.
  Thus, she spent $50 + $9= $59.
  Therefore, she got back change of $100 - $59 = $41.