Gertrude Baker

Gertrude Baker, or "Mathlete" is a smart girl with 2 sisters. Her upgrades give her extremely fast thinking skills. In Book 3, 'The Cheerleaders of Doom' she changes her name to Lilly, joins a cheerleading squad, and steals treasure from alternate universe. She is trapped on another Earth when she fights Screwball, a.k.a. Heathcliff Hodges.