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

1) 11 2/3 - 8 3/4 = 3 (8-9)/12= 2 (20-9)/12 = 2 11/12

2) 3 1/3 + 2 5/6 = 5 (2+5)/6 = 6 1/6

3)  2 11/12 + 6 1/6 = 8 (11+2)/12 = 9 1/12

4) 9 1/12 - 4 7/12= 5 (1-7)/12 = 4 (13-7)/12 = 4 6/12 = 4 1/2