Final Cover - For Printing

Considering the set of vowels in the English alphabet again, if B denotes this set,

then in set builder form the set is denoted as,

B = {x| x is a vowel in English alphabet}

This concept also has to be explained to the child orally, focusing on the difference

between the roster form and the set builder form. The set builder method is also

called as descriptive method.

14. Subset
    If A and B are any two sets, then B is a subset of A, if A contains all the elements
    which are contained in B.

Eg. : Let, A = {1, 2, 3, 4}

B = {2, 4}

Here A contains all the elements which are contained in B and so B is a subset of A

(also can call A as the superset of B).

To explain the concept to the child, ask him/her to consider the students, both boys

and girls of his/her class as a set. Of this set, ask him to think of boys as one element

and the girls as another element. Here, both the groups of boys or girls are subsets of

the set namely, the students in the class.

15. Power Set
    A set which contains all the subsets of the given set is called the power set.

Eg. : Let A = {1, 2}

Then the power set of A denoted as P(A) is given by,

Observe that if a set has 2 elements then its power set will be having 4 (=2^2 ) subsets.

In general, if a set A has ‘n’ elements then its power set P(A) will be having

2 n elements.