(1) [12 4/7 + 2 3/14] - 2 6/14

(2) [5 1/2 + 2 3/4] - 3 1/2

(3) 10 5/16 -[5 1/4 + 2 9/16]

(4) 6/9 + 5/18 + 1 3/6

please,help!