Помогите! Нужно решить по действиям

1) 0,9*11/12=9/10*11/12=3*3/10 * 11/3*4=3/10*11/4=33/40
2) 4 11/15-1 7/12=4-1+11/15-7/12=3+11/15*=-7/12=3+ 11*4/15*4-7*5/12*5=3+44/60-35/60=3+9/60=3+3*3/20*3=3 3/20
3)3 3/20:8 4/10=3 3/20:8 2*2/2*5=3 3/20:8 2/5=63/20*:42/5=63/20*5/42=21*3/5*4*5/21*2=3/4*1/2=3/8
4) 33/40-3/8=33/40-3*5/8*5=33/40-15/40=33-15/40=18/40=9*2/20*2=9/20

1) 0,6*5/6=6/10*5/6=2*3/2*5*5/6=3/5*5/6=3/5*5/3*2=1/1*1/2=1/2
2) 3 5/9-2 2/15=3-2+5/9-2/15=1+5/9-2/15=1+5*5/9*5-2*3/15*3=1+25/45-6/45=1+25-6/45=1+19/45=1 19/45
3) 1 19/45:9,6=1 19/45:9 6/10=1 19/45:9 2*3/2*5=1 19/45:9 3/5=1*45+19/45:9*5+3/5=64/45:48/5=64/45*5/48=164/5*9*5/16*3=4/9*1/3=4*1/9*3=4/27
4) 1/2-4/27=1*27/2*27-4*2/27*2=27/54-8/54=19/54

0,9 * 11/12 - (4 11/15 - 1 7/12) : 8,4 = 9/20
1) 4 11/15 - 1 7/12 = 4 44/60 - 1 35/60 = 3 9/60 = 3 3/20
2) 0,9 * 11/12 = 9/10 * 11/12 = 33/40
3) 3 3/20 : 8,4 = 3,15 : 8,4 = 0,375
4) 33/40 - 0,375 = 0,825 - 0,375 = 0,45 = 45/100 = 9/20

0,6 * 5/6 - (3 5/9 - 2 2/15) : 9,6 = 19/54
1) 3 5/9 - 2 2/15 = 3 25/45 - 2 6/45 = 1 19/45
2) 0,6 * 5/6 = 6/10 * 5/6 = 1/2
3) 1 19/45 : 9,6 = 64/45 : 96/10 = 64/45 * 10/96 = 4/27
4) 1/2 - 4/27 = 27/54 - 8/54 = 19/54