1.The probability is positive and less than or equal to 1.
0 ≤ p(A) ≤ 1
2. The probability of the sure event is 1.
p(S) = 1
3.If A and B are mutually exclusive, then:
p(A ∪ B) = p(A) + p(B)
The sum of the probabilities of an event and its complementary is 1, so the probability of the complementary event is: