That night, he emailed his mother a single line: “Tell Aunt Mira to send me the PDF for 10th grade. I think I’m ready.”

But his mother, overhearing from the hallway, poked her head in. “Luka, the Zbirka isn’t about the math. It’s about the struggle. Read the foreword.”

Luka read it twice. Then, something strange happened. He didn’t suddenly become a math prodigy. But he stopped seeing the PDF as an enemy. He saw it as a map of a dark forest, and every solved problem was a tiny lantern.

The reply came a minute later. Attached: Zbirka Zadataka Iz Matematike Za 10 Razred.pdf.

Luka opened it. The first problem stared back. He laughed, cracked his knuckles, and began.

For most students, it was just a PDF—a file passed around via USB drives, class WhatsApp groups, and a single, dog-eared printout that had been scanned so many times that the geometric diagrams looked like Rorschach tests. For Luka, however, it was a nightmare with a page number.