Answer:
864 cards
Explanation:
Goal: 15 set of cards
*72 cards in a set*
15 x 72 = 1080
15 sets of cards = 1080 cards in total
However Kareem so far has 216 cards.
To find out how much more cards Kareem need to reach his goal, you do the following:
1080 - 216 = 864
Kareem needs 864 more cards to reach his goal.
hope this helped....