How many digits are used for printing the page numbers of a book that has 163 pages?

There are 64 pages (100 - 163) that need 3 digits per page; 64 x 3 = 192. There are 100 pages (10 - 99) that need 2 digits per page; 100 x 2 = 200.

There are 9 pages (1 - 9 ) that need one digit per page; = 9.

So 9 + 200 + 192 = 401 digits.

[Assuming that the last page, an even-numbered page, has no number.]