In the Book
In the Movie
The story is narrated by the author as an omnicient voice.
The story is told from Bilbo's perspective.
History of Middle Earth detailing the Hobbit's past and the Dwarves' present state are revealed throughout the context of the story.
There is a prologue before the story begins that lays out the history for the viewer.
Frodo is not in the Hobbit.
Bilbo tells Frodo about an adventure he had a long time ago.
Bilbo becomes exasperated with Gandalf for suggesting he join him for an advanture. He leaves, but his polite nature forces him to invite the wizard to tea the next day. He regrets that decision.
This doesn't happen.
Bilbo has a fat stomach and long clever brown fingers.
He doesn't.