Number of digits from page : 1 to 9 = 9 Number of digits from page : 10 to 99 = 2 × 90 = 180 Number of digits from page : 100 to 999 = 3 × 900 = 2700 Then number of digits in 4-digits page numbers = 3189 – (9 + 180 + 2700) = 3189 – 2889 = 300 Hence, number of pages in 4 digits number =
300
4
=75 Therefore, total number of pages of the book = 999 + 75 = 1074