A=2/3-1/2 numitor comun 6
A=4/6-3/6
A=1/6
B=5/6+(1+3/4)
B=5/6+(4/4+3/4)
B=5/6+7/4 numitor comun 2
B=10/12+21/12
B=31/12
C=1/3-(5/6-1/2)
C=1/3-(5/6-3/6)
C=1/3-2/6
C=3/6-2/6=1/6
D=1-(2/5+1/10)+3/10
D=1-(4/10+1/10)+3/10
D=1-5/10+3/10
D=10/10-5/10+3/10
D=5/10+3/10
D=8/10
Succes!