But X could also approach zero from a negative value, and that would change the sign of the answer. To A Tree Set Theory is an entertaining topic in mathematics. Basically, a set is a collection of items that share some defined relationship. Thus, we can have a set of cattle , which will contain all cattle of every kind. We can also define a subset of brown cows , which is a smaller member of the cattle set.
Brown cows are still cattle, but now they have a set of their own.
Okay, now let's apply this concept to numbers . That concludes our Math Lesson.