A number cube is rolled. What is p (3 or an even number)

In order to find the probability of a 3 or an even number, we must add the probabilities of the individual events. This is done as:

P (3) = 1/6

P (even number) = 3/6 = 1/2

P (3 or even number) = 1/6 + 1/2

P (3 or even number) = 2/3