# What is Subset? Chapter 1

What is Subset? Chapter 1

What is a Subset?
If A & B are two sets, A is called a subset of B, written A ⊆ B, if, and only if, any
element of A is also an element of B.
Symbolically:
A ⊆ B
EXAMPLES:
Let
A = {1, 3, 5} B = {1, 2, 3, 4, 5}
C = {1, 2, 3, 4} D = {3, 1, 5}
Then
A ⊆ B ( Because every element of A is in B )
C ⊆ B ( Because every element of C is also an element of B )
A ⊆ D ( Because every element of A is also an element of D and also note
that every element of D is in A so D ⊆ A )
and A is not subset of C .
( Because there is an element 5 of A which is not in C )

If A & B are two sets, A is called a subset of B, written A ⊆ B, if, and only if, any
element of A is also an element of B.
Symbolically:
A ⊆ B
EXAMPLES:
Let
A = {1, 3, 5} B = {1, 2, 3, 4, 5}
C = {1, 2, 3, 4} D = {3, 1, 5}
Then
A ⊆ B ( Because every element of A is in B )
C ⊆ B ( Because every element of C is also an element of B )
A ⊆ D ( Because every element of A is also an element of D and also note
that every element of D is in A so D ⊆ A )
and A is not subset of C .
( Because there is an element 5 of A which is not in C )