1)10/12(simplific prin2)=5/6
240/600(simplific mai intai prin 10)=24/60( acum simplific prin 6)=4/10(iar acum simplific prin 2)=2/5
2)3 5/2=3×2+5/2=11/2
7 1/3=7×3+1/3=22/3
5 10/7=5×7+10/7=45/7
3)a)10/11+12/11=22/11=2
b)23/50+39/50+12/50=74/50=37/25
c)5/12+3/4+1/3=5/12+9/12+4/12=18/12=9/6=3/2