conversations.from: human
conversations.value: There are 336 books in a library. On Monday, 124 books are taken out. On Tuesday, 22 books are brought back. How many books are there now?
conversations.from: assistant
conversations.value: At the end of Monday, there are 336 - 124 = 212 books left.
  At the end of Tuesday, there are 212 + 22 = 234 books.