The part in the A section should be 28,32,36 since it is all of the numbers that belong to A that don't belong to B
The part in the B section should be 12 and 18 since it is all of the numbers that belong to B that don't belong to A
The part that belongs to the section in the middle is 24 since it is all of the values that belong to both A and B
The outside area is 12,18,24,28,32,36 because it is all of the values that are even numbers between 11 and 39 that don't belong to A or B
Hope this helps :)