If P(A \cupB)=\frac{5}{6}, P(A \capB)=\frac{1}{3} and P({\not} A)=\frac{1}{2}, then which one of the following is not correct? [NDA-I 2020]

Correct Answer is : P(A∪B)>P(A)+P(B)

P(not A and not B ) = P(not A) P(not B )