2/5 + 1/2 = 4/10 + 5/10 = 9/10
6 1/4 - 3 2/3 = 6 3/12 - 3 8/12 = 2 7/12
(1 1/2)/(1/2)= 3/2 / 1/2 = 3
5/7 + 4/7 = 9/7 = 1 2/7
2 1/8 + 4 3/8 = 6 4/8 = 6 1/2