Answer:
864 more cards Kareem need to reach his goal.
Explanation:
Given:
Kareem has 216 role-playing game cards.
His goal is to collect all 15 sets of cards.
There are 72 cards in a set.
Now, to find the number of cards more Kareem need to reach his goal.
Sets of cards his goal is = 15.
Number of cards in a set = 72.
So, to get the number of cards Kareem's goal is:

Already cards Kareem has = 216.
Now, to get the number of cards more Kareem need to reach his goal the number of cards Kareem hs from number of cards his goal is:

Therefore, 864 more cards Kareem need to reach his goal.