Division is the conclusion that just because something has a certain property, that all its parts must also have that same property. Division is the converse of Composition.
In many cases, it is necessarily true that smaller things have the same characteristics as what they make up. The percentage of chocolate in a bag of m&ms is the same as in a single m&m for instance. But the amalgamate color of a bag of m&ms(er brownish vomity?) does not translate to each little candy.
Corporation X is unscrupulous in its business practices.
Therefore, everyone working for Corporation X has no morals.
San Francisco has the most expensive rents in the United States.
Therefore, my San Francisco apartment is more expensive than one in Manhattan.