12/7*2 3/5*2 1/4 5 2/5*1 6/7*1/4 12 4/5*3 3/4-4 4/11*4 1/8 11 2/3: 7/18 28,8: 13 5/7+6,6; 2/3 1 11/16: 2,25

1 2/7*2 3/5*2 1/4  = 3 12/35*2 1/4  = 7 73/140 = 3
5 2/5*1 6/7*1/4         10 1/35*1/4        2 71/140  

1 2/7*2 3/5=9/7*13/5=117/35=3 12/35
5 2/5*1 6/7=27/5*13/7=351/35=10 1/35
3 12/35*2 1/4 =117/35*9/4=1053/140=7 73/140
10 1/35*1/4 =351/35*1/4=351/140=2 71/140
7 73/140: 2 71/140=1053/140: 351/140=1053/140*140/351=3/1=3

12 4/5*3 3/4-4 4/11*4 1/8 = 48-18 = 30 =1
11 2/3:7/18                            30       

30 12 4/5*3 3/4 =64/5*15/4=16/1*3/1=48/1=48
4 4/11*4 1/8 = 48/11*33/8= 6/1*3/1=18/1=18
11 2/3:7/18=35/3:7/18=35/3*18/7=5/1*6/1=30/1=30


28,8:13 5/7+6,6:2/3 = 2,1+9,9 = 12  =16
1 11/16:2,25                0,75        0,75  

28,8:13 5/7=28 8/10:13 5/7=28 4/5:13 5/7=144/5:96/7=144/5*7/96=3/5*7/2=21/10=
=2 1/10=2,1
6,6:2/3=6 6/10:2/3=6 3/5:2/3=33/5:2/3=33/5*3/2=99/10=9 9/10=9,9
1 11/16:2,25=1 11/16:2 25/100=1 11/16:2 1/4= 27/16:9/4=27/16*4/9=3/4=0,75 2,1+9,9=12
12:0,75=16