Let {1} be a subset of a, and let {1,2,3,4,5,} be a proper subset of A. let's find the number of sets of A

Let {1} be a subset of a, and let {1,2,3,4,5,} be a proper subset of A. let's find the number of sets of A

When there is only one subset in set a, that is {1} one
When there are two subsets in set a, that is 1 and another number = C14 = 4
When there are 3 subsets in set a = C24 = 6
When there are 4 subsets in set a = C34 = 4
When there are subsets in set a = c44 = 1
So it's 1 + 4 + 6 + 4 + 1 = 17
Don't understand can ask me. Typing is very hard, agree with my answer

How many nonempty proper subsets of set {1,2,3,4}?

Subset: 2 ^ 4 = 16
True subset: 2 ^ 4-1 = 15
Nonempty proper subset: 2 ^ 4-1-1 = 14

Write out all the subsets of set a = {1.2.3}, and point out which of them are true subsets
The question is as follows
In a hurry in a hurry in a hurry in a hurry in a hurry in a hurry
I wait online!
thank you!

Let me give you a complete solution to this problem
Solution: all subsets of set a = {1.2.3} are: {1}, {2}, {3}, {1,2}, {2,3}, {1,3}, {1,2,3}, Φ. Proper subsets are: {1}, {2}, {3}, {1,2}, {2,3}, {1,3}, Φ
We taught that