Here, we want to find the difference a subset and a proper subset
Firstly, we should notice the keyword 'proper' here
Suppose we have three sets A, B and C.
Let us give some values to drive home our point
Let;
A = {1,2,3,4,5}
B = {1,2,3,4,5}
C = {2,3,4}
We can conclude that B is a proper subset of A since all the values we have in B are in A and they have the same number of elements.
But, set C is only a subset of A because although we have all elements of C in A, but both sets do not contain the same number of elements
Symobolical-wise;
We can represent this as;
B ⊂ A while we represent the relationship between A and C as C ⊆ A