Math Trick #2 - Pick any number Pick any NATURAL number (not zero) If You Can Solve This Simple Math Puzzle in Under 10 Seconds, You May Be. I explain a classic mathematical riddle and even perform a magic trick to help illustrate the concept! Please "like" the Mystery of the Missing Dollar Puzzle. Journalist Mikael Blomkvist is aided in his search for a woman who has been missing for forty years by Lisbeth Salander, a young computer hacker. Comments .