Răspuns:
Explicație pas cu pas:
1
a)2/3
b)1/5
c)5/6
2.
a) 61/50
b) 43/34
c) 101/103
3.
7/12
.....i.....i.....i.....i.....i.....i.....i.....i.....i.....i.....i.....i
___________________=7/12
4.
17/71 ; 27/72 ; 37/73 ; 47/74 ; 57/75 ; 67/76 ; 77/77 ; 87/78 ;97/79
trebuie sa fie numere compuse: 27/72; 57/75;77/77; 87/78