Ответ:) 12/18=2/3; 6/54=1/9; 56/98=8/14; 42×24/8×21=2×3/1×1=6

2)3/1+5/22=66/22+5/22=71/22=3 5/22

11/12-7/15=55/60-28/60=27/60=9/20

11/15-3/20+1/30= 44/60-9/60+2/60=37/60

3)b-13/15=13/45

b= 13/45+13/15=13/45+39/45=52/45=1 7/45

7/36d=39/48

d=39/48÷7/36=39/48×36/7=39/12×9/7=351/84 =4 15/84

4) 11/30-1/45= 33/90-2/90=31/90 во вторые сутки

11/30+31/90=33/90+31/90=64/90=32/45- прошел за двое суток

5) 2/11<3/11; 5/22;6/22;7/22 >4/11