We are going to tell you how to remember what each of the Dewey hundreds groups represents.
In the story, the 000s are explained at the very end, after the 900s.
Here is a story to help you understand:
On the library shelves, they come at the very beginning, before the 100s.
One day, while Melvil Dewey was walking in Central Park, he saw a UFO. He became terrified of it, and ran to take cover.