You Need 4/5 Cups Of Water For A Recipe. You Accidentally Put 1/3 Cups Into The Mixing Bowl With The Dry Ingredients. How Much More Water In Cups Do You Need To Add?

You need to convert 1/3 and 4/5 into ?/15...
1/3 = 5/15
4/5 = 12/15

so you need to add .... 12-5 = 7/15 cups !!! Bit tricky to measure 7/15 cups, but its pretty much half a cup =)

7/15