Find a number?

The number is : 6

Explanation : Here we can see that from the first row the number in the center circle is equal to the half of the sum of the numbers of the circles given in left and right.
i.e for row 1 : (4 + 2)/2 = 3
for row 2 : (5 + 3 +1+1)/2 = 5
for row 3 : (6 +1 + 2 +3 +3 +1)/2 = 8
for row 4 : (7 + 2 + 4 + 3)/2 = 8

So, for row 5 : (9 + 3)/2 will be 6.