Answer :
2 1/3 + 2 1/2 = 4 + 1/3 + 1/2 = 4 + 2/6 + 3/6 = 4 + 5/6 ( both recipe );
5 - ( 4 + 5/6) = 1 - 5/6 = 6/6 - 5/6 = 1/6 cups of flour left;
5 - ( 4 + 5/6) = 1 - 5/6 = 6/6 - 5/6 = 1/6 cups of flour left;