 Hello and welcome to the session. In this session we discuss the following question which says list the elements of a complement if xi is equal to the set containing the elements 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 and set a is equal to the set containing the elements 1, 4, 5, 6, 7, 8. Before we move on to the solution, let's recall the definition for the complement of a set. If a is a subset of a universal set xi, then the set of all those elements of xi which do not belong to the set a is called the complement of a. And the complement of a is denoted by this or this or this. So we say a complement is equal to the set containing the element x such that x belongs to xi and x does not belong to a. This is the key idea that we use for this question. Let's proceed with the solution now. We are given the universal set xi which is equal to the set containing the elements 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10. And we are given a set a equal to the set containing the elements 1, 4, 5, 6, 7 and 8. We have to find out a complement. We know that a complement is equal to the set containing the element x such that this x belongs to xi and x does not belong to a. This means that a complement consists of those elements which belongs to the universal set but they do not belong to the set a. So when we compare the sets xi and a we find that a complement is equal to the set containing the elements 2, 3, 9 and 10. Since 2, 3, 9 and 10 they belong to the universal set xi but they do not belong to the set a. So this is our final answer where we have found the complement of the set a. This completes the session. Hope you have understood the solution of this question.