Watch: The probability rules Opens a YouTube search: pick a video that clicks for you Range 0 ≤ P(A) ≤ 1 ; P(not A) = 1 − P(A) Addition rule P(A or B) = P(A) + P(B) − P(A and B) Subtract the overlap. Mutually exclusive ⟹ P(A and B) = 0. Multiplication (independent) P(A and B) = P(A) × P(B) Only when A and B are independent. Conditional probability P(A\mid B)=\frac{P(A\cap B)}{P(B)} Probability of A given B has occurred.