In the first line, we are going to have that if you put 7 then to have the sum rigth the next space have to be 9, following that idea the space down of the 9 have to be also 7 and the first space on the second line have to be 19. So we are going to have 7 + 9 = 16 in the first line and in the second line 19 - 7 = 12, and the other two operations are going to be solve also 7 + 19 = 26 and 9 + 7 = 16.
Then the answer is 7 + 9 = 16 in the first line and in the second line 19 - 7 = 12.