3 - ( 1/6 + 2/3^2 ) = 3 - ( 1/6 + 4/6 ) = 3 - 5/6 = 2 1/6
4 5/6 - ( 2 3/8^3 + 7/12^2 ) 4 5/6 - ( 2 9/24 + 14/24 ) = 4 5/6^4 - 2 23/24 = 4 20/24 - 2 23/24 = 3 44/24 - 2 23/24 = 21/24
7 - ( 2 3/4^3 + 7/12 ) = 7 - ( 2 9/12 + 7/12 ) = 7 - 3 1/3 = 3 2/3
6 1/4 - ( 3 2/5^8 + 3/5^5 ) = 6 1/4 - ( 3 16/40 + 15/40 ) = 6 10/40 - 3 31/40 = 2 19/40