30 4/5-1 2/5*(1 4/5*(12 7/12-9 19/36)-17/35*1 11/34)=

30 4/5 - 1 2/5 * (1 4/5 * (12 7/12 - 9 19/36) - 17/35 * 1 11/34) = 24
1) 12 7/12 - 9 19/36 = 12 21/36 - 9 19/36 = 3 2/36 = 3 1/18
2) 1 4/5 * 3 1/18 = 9/5 * 55/18 = 11/2 = 5 1/2
3) 17/35 * 1 11/34 = 17/35 * 45/34 = 9/14
4) 5 1/2 - 9/14 = 5 7/14 - 9/14 = 4 21/14 - 9/14 = 4 12/14 = 4 6/7
5) 1 2/5 * 4 6/7 = 7/5 * 34/7 = 34/5 = 6 4/5
6) 30 4/5 - 6 4/5 = 24