To find out how many pages Van fills with his new baseball cards, we need to divide the total number of cards by the number of cards that fit on each page.
He has 45 baseball cards and each page holds 9 cards.
So, we can divide 45 by 9.
45 / 9 = 5
Therefore, Van fills 5 pages with his new baseball cards.
It's worth noting that this method gives the number of full pages that are filled and if there are any remaining cards, we have to add one more page for the remaining cards.