We will look at the additive and multiplicative principles in a slightly different way. Instead of thinking about event \(A\) and event \(B\text{,}\) we want to think of a set \(A\) and a set \(B\text{.}\) The sets will contain all the different ways the event can happen. (It will be helpful to be able to switch back and forth between these two models when checking that we have counted correctly.) Here's what we mean:
in-context