3целых 17/20: (3 целых 2/5 +1 целая 11/15) (1 целая 7/10+4/5): 1 целая 9/35: (1 целая 1/5 +2/3 (8 целых 7/12 - 2 целых 5/8): 2 целых 1/6

3 17/20 : (3 2/5 + 1 11/15)(1 7/10 + 4/5) : 1 9/35 : (1 1/5 + 2/3)(8 7/12 - 2 5/8) : 
: 2 1/6 = 

1) 3 2/5 + 1 11/15 =3+1 + 10/15 = 4 10/15
2) 1 7/10 + 4/5 = 1 15//10
3) 1 1/5 + 2/3 = 1 9/15
4) 8 7/12 - 2 5/8 = - 6 1/24
5) 4 10/15 х 1 15/10 = 70/15 х 25/10 = 35/3
6) 1 9/15 х (-6 1/24) = 24/15 х (- 145/24) = 29/3
7) 3 17/20 : 35/3 = 77/20 х 3/35 = 33/100
8) 33/100 : 1 9/35 = 33/100 : 44/35 = 33/100 х 35/44 = 21/80
9) 21/80 : 29/3 = 21/80 х 3/29 = 63/2320
10) 63/2320 : 2 1/6 = 63/2320 : 13/6 = 63/2320 х 6/13 = 189/15080