The pages of a book are numbered and it's found that 495 digits are used How many pages were there?

There are 9 pages that use a single digit (pages 1-9), leaving 495 digits - 9 pages × 1 digit/page = 486 digits

There are 90 pages that use 2 digits (pages 10-99), leaving 486 digits - 90 pages × 2 digits/page = 306 digits

There are 900 pages that use 3 digits (pages 100-999); this would be 2,700 digits, so the number of pages is somewhere in the hundreds.

306 digits ÷ 3 digits/page = 102 pages in the hundreds.

→ total number of pages = 102 + 90 + 9 = 201 pages.