Avenn diagram is shown below: a venn diagram showing two categories, a and b. in the a only circle is 2 and 4, in the b circle is 5 and 6, in the intersection is 1 and 7, and in outside the circles is u what are the elements of (a ∩ b) ' ?

According to the information given above, 
A = [2, 4]
B = [5, 6]
A Intersection B = [1, 7]
The element of {A N B]! are those elements which are in both set A and set B with the exception of the elements that forms the intersection between them.
Thus, for the question given above,
{A N B]! = [2, 4, 5,6].