So the product rule states that the probability of two or more independent events taking place or occurring is equal to the product of their individual probabilities. And that's exactly why we call the product rule the product rule because it involves the word product. So to calculate or to use the product rule, we actually have to multiply the individual probabilities as we'll see in just a moment. Now in order to actually fully understand what the product rule tells us, we have to define what it means for two or more events to be independent of one another. So to demonstrate the independence of events, let's actually use the following coin. So we're going to flip a coin twice.