This is a tricky riddle indeed. Each page in a book has a odd and even number( assuming its printed both sides).Hence page number looks like 1-2, 3-4, 5-6 and so on..Now looking at above riddle.
7-8 is single page
99-100 is single page
101-102 is single page
221-222 is single page
223-224 is single page.
So total of 5 pages