At first, let us complete the digram
a)
b)
Means write all the elements in X and Y, then
c)
Means write the common elements in X and Y
Since there are no common elements in X and Y, then
d)
The number of elements in
is 4 + 4 = 8 elements
#(XUY) = 8
e)
The number of elements in
is zero because there are no common elements between X and Y
#(XnY) = 0