Page problem math

Question

Stephanie began reading her library book at the top of page 7. She finished reading at the bottom of page 33. How many pages did she read?

Answer 1

7 to 10 is 4 pages

11 to 20 is 10 pages

21 to 30 is 10 pages

31 to 33 is 3 pages

Answer 2

If you make the problem a simple one, you'll be able to see how to solve it. Let's say she begins reading at the top of page 7 and finishes at the bottom of page 8. Then she would have read page 7 and page 8 or 2 pages. If she read to the bottom of page 9, she would have read 3 pages, right? So you can subtract the two page numbers and add 1:

Starts Finishes Number of pages read

top 7 bottom 8 8 - 7 + 1 = 2

top 7 bottom 9 9 - 7 + 1 = 3

top 7 bottom 33 33 - 7 + 1 = ?