Inclusive means that you include the outermost numbers of a set.

For instance, {1,2,3} inclusive means that you are talking about 1 and 3 as well as 2.

Therefore, when a problem says something like "4 through 6 inclusive" it means {4,5,6}. If it siad "4 though 6 not inclusive" it would mean {5} and only that number!