Answer: 324 cards.
Explanation:
Hi, to answer this question we have to multiply the number of pages in the album (72) by the number of cards that each page holds (9):
Mathematically speaking:
72(9) = 648 cards in the album
Since half of the pages are full, we have to divide the previous result by 2.
648/2 = 324 cards
Feel free to ask for more if needed or if you did not understand something.