Răspuns :
Respectand conditiile enuntului , avem:
51/3=17+0/3 ; 21/7=3+0/7 ; 15/12 =1 + 3/12=1+1/4 ;
17/3=15/3+2/3=5+2/3 ; 19/5=15/5+4/5=3+4/5 ;
51/3=17+0/3 ; 21/7=3+0/7 ; 15/12 =1 + 3/12=1+1/4 ;
17/3=15/3+2/3=5+2/3 ; 19/5=15/5+4/5=3+4/5 ;