1) If P = { x | x is a prime number 10 and 12 } then P = {11}

As we observe that there is only one element in set P.

n(P) = 1

so

2) If A = { x| x ∉ 3 < x < 5 } then

A = { x| x ∉ 3 < x < 5 }

A = { 4}

As the set A contains only one element so set A is a singleton set.

If A= { x | x is a prime number, x<10 } then A= { 2,3,5,7}

Here then there are only 4 elements which satisfies the given condition.

Thus,

set C = { 10,20,30,40,50,60,…}

As the number of elements in set C are infinity (uncountable)

Thus,

( Greek letter ‘phi’)

Thus n(φ) = 0

It is also known as

set A ={ 18 < x < 19}

So between 18 and 19 there is no element.

Thus,

• Sets

• Representation of Set

• Cardinal Number

• Types of Sets

• Pairs of Sets

• Subset

• Complement of Set

• Union of the Sets

• Intersection of Sets

• Operations on Sets

• De Morgan's Law

• Venn Diagrams

• Venn-diagrams for sets

• Venn-diagrams for different situations

• Problems on Intersection of Two Sets

• Problems on Intersection of Three Sets