2 - [ 3 - ( 4 / 3 + 1 / 2 ) ] = 5/6
= 2 - [ 3 - ( 8 / 6 + 3 / 6 ) ] =
= 2 - ( 3 - 11 / 6 ) =
= 2 - ( 18 / 6 - 11 / 6 ) =
= 2 - 7 / 6 =
= 12 / 6 - 7 / 6 =
= 5 / 6
