Simplify the following text for a Grade 4 native English-speaking person.
Original: In the first edition of The Hobbit , Gollum willingly bets his magic ring on the outcome of the riddle-game , and he and Bilbo part amicably . In the second edition edits , in order to reflect the new concept of the ring and its corrupting abilities , Tolkien made Gollum more aggressive towards Bilbo and distraught at losing the ring .
Simplified: Gollum can not find his ring , and realizes that Bilbo has it .