I am having trouble with this thing. It says,

Let A={ø, {ø}, {{ø}}}.

(a) Determine which of the following are elements of A: ø, {ø}, {ø,{ø}}.

(b) Determine |A|

(c) Determine which of the following are subsets of A: ø, {ø}, {ø,{ø}}.

For d-i, determine the indicated sets.

(d) ø∩A

(e) {ø}∩A

(f) {ø,{ø}}∩A

(g) ø∪A

(h) {ø}∪A

(i) {ø,{ø}}∪A

For A, I got ø, {ø}

B, 3

C, ø,{ø}

D, ø

E, {ø}

F, nothing

Now, I'm just not sure what I'm doing. It's all these stupid empty sets.