(5целых 1/30-2целых 3/5-2/15+-6целых 11/12+1/4)

(5 1/30 - 2 3/5 - 2/15 + 6) - (7 - 6 11/12 + 1/4) = 7ц. 29/30
1) 1 скобка:
151/30 - 13/5 - 2/15 + 6 = 151/30 - 78/30 - 4/30 + 180/30 = 249/30 = 8 9/30 = 8 3/10,
2) 2 скобка:
84/12 - 83/12 + 3/12 = 4/12 = 1/3,
3) 8 3/10 - 1/3 = 83/10 - 1/3 = 249/30 - 10/30 = 239/30 = 7 29/30