Răspuns:
a) 1/2+6/2=7/2
1/2+5/2=6/2
1/2+9/2=10/2
b)1/3+7/3=8/3
1/3+1/3=2/3
1/3+9/3=10/3
c)2/5+3/5=5/5
2/5+2/5=4/5
2/5+7/5=9/5