Hello, I am unsure as to why the probability of A U B = P(A) + P(B) for sets A and B being disjoint. Why do we add the two probabilities? Is it because the sample space remains the same but now we add the numerators as the number of events have increased and that is why we are adding the two?? Can anyone give me a good intuitive explanation? I tried solving the problem myself but I cannot figure out how to arrive at the answer. An intuitive explanation will really help. Thanks in advance for your answers!