1038. A piece of the book fell out. The first page of the piece has the number 163, and the number of the last page consists of the same digits but in a different order. How many sheets fell out of the book
$\triangle$ The last page of the piece has the number 316, as it must end with an even digit. Now we find the number of pages, and then the number of sheets in the piece:

$$
316-162=154, \quad 154: 2=77
$$

Answer: 77.