Consider the above Venn-diagram. The set {2,9,10} represents ___.
(A∪B)′
Note from the Venn diagram that A∪B={4,7,1,6,5,8,3}.
The complement of A∪B is the set of all those elements of U, which are not in A∪B.
∴(A∪B)′={2,9,10},represented by the portion shaded in green.