10/12=10/12:2=5/6

0,5=5/10=3/6

8/16=8/16:8=1/2=3/6

2/3=4/6

7=7/1=42/6

15/18=15/18:3=5/6

7/21=7/21:7=1/3=2/6

75/90=75/90:15=5/6

1/2=3/6

3/18=3/18:3=1/6