The sentence "Your solar system includes eight planets and one sun" can be best explained in math terms as a set.

Here's why:

* Sets are collections of distinct objects.

* In this case, the objects are "planets" and "sun".

* The sentence describes the elements of the set (planets and sun) and their cardinality (there are eight planets and one sun).

We could represent this mathematically as:

* Solar System = {Planet 1, Planet 2, ... Planet 8, Sun}

This notation shows that the Solar System is a set containing eight planets and one sun.