6 5/9 -(2 5/9 + 7/9)= (2 6/7 + 3 4/7)- 2 6/7 = 7 6/13 -211/13-2/13=

1) 6 5/9 - (2 5/9 + 7/9) = (6 * 9 + 5)/9 - ((2 * 9 + 5)/9 + 7/9) = (54 + 5)/9 - ((18 + 5)/9 + 7/9) = 59/9 - (23/9 + 7/9) = 59/9 - 23/9 - 7/9 = (59 - 23 - 7)/9 = 29/9;

2) (2 6/7 + 3 4/7) - 2 6/7 = ((2 * 7 + 6)/7 + (3 * 7 + 4)/7) - (2 * 7 + 6)/7 = ((14 + 6)/7 + (21 + 4)/7) - (14 + 6)/7 = (20/7 + 25/7) - 20/7 = (20 + 25 - 20)/7 = 25/7;

3) 7 6/13 - 211/13 - 2/13 = (7 * 13 + 6)/13 - 211/13 - 2/13 = 97/13 - 211/13 - 2/13 = (97 - 211 - 2)/13 = -116/13.