SOLUTION: DERIVE: P(A-B)=P(A)-P(A intersection B)

Question 1147962: DERIVE: P(A-B)=P(A)-P(A intersection B)
Answer by ikleyn(52858) (Show Source): You can put this solution on YOUR website!
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It is TRUE because (A \ B) = ( A \ (A intersection B) ) at the "set level".

The last identity (at the set level) you can easily prove/check considering elements from (A \ B) and ( A \ (A intersection B) ).

            "The elements of the subset   (A \ B)   are those and only those 

             elements of  A,  that do not belong to  (A intersection B)."

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