Question

should we place in the missing term

Answer 1

In each column if You add 2nd and 3rd row elements you will get 1st row elements.

for eg:
43+35=78
39+58=97

hence

67+13=80.

hope u get it

Answer 2

Yes 80 will be the right answer bcoz
adding first and second numbers in the column we got the third number in the column .
so,67+13=80