Răspuns:
3)
a) 9/9+14/27=27/27+14/27=41/27
b) (18/102+8/102)+14/17=26/102+84/102=110/102
c) (1/33+9/33)+2/11=10/33+6/33=16/33
d) 2/5+(1/20+16/20)=8/20+17/20=25/20