Hello, MATNTRNG!

There's no formula for this problem.

I had to baby-talk my way through it.

In numbering the pages of a book, a printer used 3289 digits.

How many pages were in the book, assuming

that the first page in the book was number 1?

. .

Hence: . digits were used

. . in the first 100 four-digit numbers.

. . . .

Therefore, the book had 1099 pages.