To find out how many kids are playing catch, you subtract the number of kids playing basketball from the total number of kids.
There are 10 kids total, and 6 kids are playing basketball:
10 - 6 = 4 kids are playing catch.
The addition fact that can be used to find the answer is:
6 + 4 = 10.
So, the correct response is:
6 + 4 = 10.