Pls explain about subset and proper subset - Maths - Theory of Sets

Question

Pls explain about subset and proper subset

Lovina Kansal · Accepted Answer

Subset of a Set
A set is a collection of elements, such as
integers, fruits etc A set B is a subset of a set A if all element
of B are also element of A Such a relation between sets is denoted
by B ⊆ A If B ⊆ A and B ≠ A we call B a proper subset
of A and write B ⊂ A
Example: A = {1, 2, 3, 4,
5, 6} B = {1, 2, 3}
B ⊆ A: B is subset of A, because all
element of B are also element of A
Proper Subset
If A is a subset of B such that there exists at least one element
of B not contained in A, then A is a proper(or
strict) subset of B
For example, if A = {1, 2} and B = {1, 2, 3} then A is a proper
subset of B