## Let U = {1, 2, 3, 4, 5, 6, 7, 8, 9}, A = {1, 2, 3, 4}, B = {2, 4, 6, 8} and C = {3, 4, 5, 6}. Find (B-C)'

The universal set is the set of all the elements or members of all related sets. We usually use the capital letter "U" to denote a universal set.

## Answer: For U = {1, 2, 3, 4, 5, 6, 7, 8, 9}, A = {1, 2, 3, 4}, B = {2, 4, 6, 8} and C = {3, 4, 5, 6}, (B-C)' = {1, 3, 4, 5, 6, 7, 9}.

A set is defined as a collection of objects. Each object inside a set is called an 'element'.

**Explanation:**

Let's calculate the set for (B-C).

The elements of the set (B-C) are the elements that are present in set B but not in C.

(B-C) = {2, 8}

Now, the set (B-C)' represents all the elements that are present in the universal set U = {1, 2, 3, 4, 5, 6, 7, 8, 9} but not in the set (B-C) = {2, 8}.

(B-C)' = {1, 3, 4, 5, 6, 7, 9}