1/9,1,7,35?,(105?)
3/15,1/3,3/7,1/2,(5/9 )=1/5,2/6,3/7,4/8,5/9
1/16,2/13,2/5,8/7,4 ,(32)=1/16,2/13,4/10,8/7,16/4,32