1. For numbering the pages of a dictionary, 6869 digits are used. How many pages does the dictionary have?
Solution. For numbering the first 999 pages, the following digits are required:

$$
9+2 \cdot 90+3 \cdot 900=2889 \text { digits. }
$$

There remain $6869-2829=3980$ digits. With these, an additional $3980: 4=995$ pages can be numbered. Therefore, the total number of pages in the dictionary is $999+995=1994$