7/8 и 2/3;
7/8=21/24
2/3=16/24
6/7 и 4/5:
6/7=30/35
4/5=28/35
3/5 и 4/9;
3/5=27/45
4/9=20/45
8/11 и 5/6;
8/11=48/66
5/6=55/66
9/10 и 1/3 ;
9/10=27/30
1/3=10/30
11/15 и 4/7;
11/15=77/105
4/7=60/105
5/8 и 1/11;
5/8=55/88
1/11=8/88
17/20 и 2/9
17/20=153/180
2/9=40/180