what is 7 over 9 plus 11 over 13?

7/9 + 11/13

Find a common denominator:  multiply  9 x 13  to get  117

To change 7/9:   (7 x 13) / (9 x 13)  =  91/117

to change 11/13:  (11 x 9) / (13 x 9)  =  99/117

91/117 + 99/117  = 190/117                       (Add the numerators 91 + 99; keep the denominator as it is.)