Answer:
3
Explanation:
I'm going to assume you meant "How many 2/9 cup serving are in 7/9 cup of juice" (since there are no 7/9 cups of serving in 2/9 cups of juice, since 7/9>2/9, and you can't have a serving of something greater than the amount you have).
In this case:
7/9 divided by 2/9=3
Since 7/9 and 2/9 have the same denominater, you can cross them off, since when you divide them, 9 divided by 9=1. 7 divided by 2=3.5, but I'll assume you want full cups.