prompt: The library has 9,900 books. Over the summer, they sold some books. If only four sixths of the books are left, how many did they sell?
messages.content: The library has 9,900 books. Over the summer, they sold some books. If only four sixths of the books are left, how many did they sell?
messages.role: user
messages.content: A sixth of the books is 9900/6 = <<9900/6=1650>>1650 books.
  Only 4*1650 = <<4*1650=6600>>6600 books are left.
  The library sold 9900-6600= <<9900-6600=3300>>3300 books over the summer.
  #### 3300
messages.role: assistant