Forced to actually think, Maksim used the GDZ as a hint rather than a script. He traced the logic, found the error, and solved it himself using the correct numbers. He closed the tab, feeling like a hacker who had outsmarted both the textbook and the internet.

Problem #452 was a wall. It involved proportions, percentages, and a cyclist who seemed to be traveling at an improbable speed. Maksim’s brain was foggy. He looked at his smartphone, its screen glowing like a forbidden treasure.

"Wait," Maksim whispered. "That’s not right. The discount was 15%, not 25%."