Ist symbol C represent the relationship between two sets...

' C ' is read as

' is a subset of ' Or ' Is in ' Or ' is contained in '

For example : A = Number of students of class 11th..

B = Number of students of your school.

Clearly , Set A fits in the set B...As every MEMBERS or elements of set A is in ( belongs to ) set B...

So we say here A is a subset of B Or A is in B or A is contained in B...We use notation for this as FOLLOW..

A ' C ' B => A is a subset of B

Second Notation we use when two or more sets are Combined together...It is basically one of the operation of set...NAME of the operation is UNION...

for example : A = { 1 , 2 } And B = { 3 }

then A U B = { 1 ,2} U { 3 } = { 1,2,3 }

Third Notation is again a operstion of the set named as INTERSECTION...This operation is used when we consider the common between the two sets...

For example : A = { 1 ,2 } , B = { 2 , 3 }

then A intersection B = { 2 }

Last symbol is used to represent the relationship between Set and its elements..

€ => read As many ways

a € A => here a = element and A = set

above expression read as many ways:

a € A => a belongs to A Or a is in set A Or a is a member of A Or a is an element of A...

For example : N = set of all natural number.

If we want to write 1 is a nature number then we simply write it as

1 € N

So you can read 1 € N as follow

=> 1 is a natural number

=> 1 is in set N

=> 1 is a member of N

=> 1 is an element of N and so on...

As we know that -3 is not a natural number..so we write it as -3 £ N

=> - 3 does not belong to N or not a member of N or so on...

Hope this help ...