5 1/3 :6 2/5 + (12 : 3 3/5 - 2/3) *2/3 + 7 2/5

1. 5 1/3:6 2/5 = 16/3:32/5 = 16/3·5/32 = 80/96 = 5/6;2. 12:3 3/5 = 12:18/5 = 12·5/18 = 60/18 = 10/3;3. (10/3 - 2/3)·2/3 = 8/3·2/3 = 16/9;4. 5/6 + 16/9 + 7 2/5 = 5/6 + 16/9 + 37/2 = 5·3/6·3 + 16·2/9·2 + 37·9/2·9 = 15/18 + 32/18 + 333/18 = 380/18 = 21 2/18 = 21 1/9.