2 1/2 + 5 1/3 + 1 1/4 =

2 1/2 = 5/2, 5 1/3 = 16/3, 1 1/4 = 5/4
5/2 + 16/3 + 5/4 = 30/12 + 64/12 + 15/12 =109/12 = 9 1/12