if A = {10,11,12} and B = {13,14}, what is A - B?

Answer 1

The set {A-B} contains all elements that are in A but not in B. It removes all elements of B from A.

But in this case, there are no common elements, hence, A-B = A = {10,11,12}

Answer 2

Mathematically,

A - B = A - (A ∩ B)