45:3 6/13-13.6+1 3/8=31/40
1)45:3 6/13=13
2)13-13.6=-0.6
3)-0.6+1 3/8=0.775=775/1000=31/40
37:2 3/17-17.8+1 2/7=17/35
1)37:2 3/17=17
2)17-17.8=-0.8
3)-0.8+1 2/7=17/35
6 3/7:1 6/7=4.5:Х
45/13=4.5:Х
Х=4.5:45/13
Х=1.3=1 3/10
1 1/3: 5 2/9=Х:4.7
12/47=Х:4.7
Х=4.7*12/47
Х=1.2=1 2/10=1 1/5