Determine if the set A = {1, 2, 3, 4, 5} is a proper subset of the set B = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}.

Step 1 ：A set A is said to be a proper subset of another set B if every element of A is in B, but B contains at least one element not in A.

Step 2 ：We can see that every element of set A = {1, 2, 3, 4, 5} is in set B = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}.

Step 3 ：Additionally, set B contains elements (6, 7, 8, 9, 10) that are not in set A.

Step 4 ：Therefore, set A is a proper subset of set B.