2*3=6
1/2=(1*3)/(2*3)=3/6
1/3=(1*2)/(3*2)=2/6
2*7=14
1/2=(1*7)/(2*7)=7/14
1/7=(1*2)/(7*2)=2/14
15*16=240
2/15=(2*16)/(15*16)=32/240
3/16=(3*15)/(16*15)=45/240
10*17=170
3/10=(3*17)/(10*17)=51/170
4/17=(4*10)/(17*10)=40/170
3*11=33
9/3=(9*11)/(3*11)=99/33 (...=3)
4/11=(4*3)/(11*3)=12/33
9*8=72
2/9=(2*8)/(9*8)=16/72
3/8=(3*9)/(8*9)=27/72