The probability of a multi-stage events that are independent is the product of all of them. Probability is basically the desirable outcomes over the total outcomes. When rolling a die, there are 6 different numbers you can roll, meaning six different outcomes. There are 3 outcomes where you can roll an even number: 2, 4, and 6. And it's the same with odd numbers: 1, 3, and 5. So the probability of rolling an even number is 3 / 6 or 1 / 2 and the probability of an odd number is the same, 1 / 2. Now, since the probabilities are the same at each stage, we can multiply 1 / 2 to itself 6 times or (1/2)^6 which evaluates to 1 / 64.
