Numerical Riddle: Find the Missing Number in the Picture

If you see the tables you will find the connection between the numbers as;

7 + 9 + 5 – 3 – 6 = 12 &

6 + 4 + 8 – 2 – 9 = 7

So we can find the missing number as;

8 + 11 + 17 -1 – 2 = 33

Answer = 33