How can you prove that sets (A-B) ∩ (A ∩ B) = ∅?
How do I prove that for all sets A, B, and C, (A - B) - C = (A - B) - (A-C)?

Please tell me if those questions are the same.
A: no

How many genders, or sexes, are there?
How many distinct genders are there in human race?

Please tell me if those questions are the same.
A: no

How do you sell things at school?
How should I sell things?

Please tell me if those questions are the same.
A:
no