When the teacher, Mrs. Belova, called him to the board to explain the most difficult problem in the Ivanova workbook, Max didn't just give the answer. He explained why the equilibrium shifted. He spoke with a confidence that made Mrs. Belova lower her glasses in surprise.

"You don't want the answers," the message read. "You want the logic ."

Page three of the search results led him to a forum that looked like it hadn't been updated since 2005. A user named ProfitProphet had posted a single link: "The Key to Ivanova." Max clicked, expecting a PDF. Instead, a chat window popped up.

Max rolled his eyes and typed back, "No, I definitely want the answers. This is due in six hours."

"If I give you the answers," ProfitProphet replied, "you'll pass the unit. If I teach you the game, you'll own the market. Look at Problem 4.2. Don't calculate the tax—calculate the human greed."

He never found that forum again, but he kept the workbook. On the inside cover, he scribbled: Economics isn't about money; it’s about why we choose what we choose.