2. In the notebook, a double leaf (sheet) is torn out. The page numbers on the torn-out leaves are formed by the following digits: $0,1,1,3,3,3,4,5,6,9$. What were the page numbers on the torn-out leaf? Find all possible options and prove that there are no others.
Answer: 59 / 60 / 133 / 134.

Solution:

Of the four numbers on the sheet, two are even, and their sum is 194; therefore, they end in 0 and 4. Then the odd numbers paired with them end in 9 and 3. From the remaining digits 1,1,3,3,5,6, we need to form the beginnings; it is clear that this can be done in only one way.