(topic: Algebraic Variables) - The Hacker challenges Jackie, Matt and Inez to a contest on cyber-wide television! In order to prove to all of Cyberspace that Hacker's not as powerful or smart as he seems - the kids return to Topsy-Turvy Island on the Northern Frontier for the contest. Their mission is to power up a Mini-Wreaker using cyber-fireflies of varying power before the island turns inside out at sunset. The kids must use algebraic equations to determine how many Gleamers - and how much power - they'll need. The Big Idea: When you use a letter to stand in for a number that repeats or changes in a problem, you can simplify the arithmetic and make the problem easier to solve.