1/2*1/3=
1/4*3/4=
1/5*2/3 =
2/4*1/2=
3/5*4/7=
2/5*3/10=
3/4*5/8=
6/7*8/9=
3/6*3/9=
8/9*5/6=
1/2:1/3=
1/4:3/4=
1/5:2/3=
2/4:1/2=
3/5:4/7=
2/5:3/10=
3/4:5/8=
6/7:8/9=
3/6:3/9=
8/9:5/6=