21 books • 5 series
Book #1: The Magic Eraser #1
Book #2: The Rewindable Clock #2
Book #3: The Ridiculous and Wonderful Rainbow Hat #3
Book #4: The Interdimensional Fish Sticks #4
Book #1: Math Mysteries: The Triplet Threat
Book #2: Math Mysteries: The Fall Festival Fiasco
Book #1: The Riverman
Book #2: The Whisper
Book #3: The Storyteller