__3.2a Subsets__**1.**If every element of a set

*A*is also an element of a set

*B*, then

set

*A*is called

**subset**of set

*B*.

**2.**The symbol ⊂ is used to denote ‘is a subset of’.

*A*= {11, 12, 13} and

*B*= {10, 11, 12, 13, 14}

Every element of set

Therefore $A\subset B.$

*A*is an element of set*B*.Therefore $A\subset B.$

**$A\subset B.$ can be illustrated using Venn diagram as below:**

3.

3.

**4.**The symbol $\not\subset $ is used to denote ‘is not a subset of’.

**5.**An

**empty set**is a

**subset**of any set.

For example,
$\varnothing \subset A$

**6.**A set is a

**subset**of

**itself**.

For example,
$B\subset B$

**7.**The number of subsets for a set with

*n*elements is

**2**.

^{n} For example, if

*A*= {3, 7} So

*n*= 2, then number of subsets of set*A*= 2^{2}= 4 All the subsets of set

*A*are { }, {3}, {7} and {3, 7}.