He stopped copying. Instead, Mark looked at the next problem in the Shabulin manual and tried to solve it himself on a piece of scratch paper. He got stuck halfway through, looked at the GDZ for a hint to get past the roadblock, and then finished the problem on his own.

"Excellent work, Mark," Nadezhda Petrovna said with a rare, approving smile. "I can see you really studied the didactical materials."

The dusty cover of the algebra manual read Didakticheskie Materialy po Algebre dlya 10 Klassa by Shabulin. For Mark, a tenth-grader with a heavy backpack and an even heavier dread of mathematics, that book was a daily source of anxiety. It was filled with complex equations, trigonometric functions, and probability problems that looked more like ancient hieroglyphs than schoolwork.

A week later, Nadezhda Petrovna returned the graded tests. She stopped at Mark’s desk and placed his paper face down. Mark nervously flipped it over. In bright red ink at the top was a "5"—the highest grade.

The rest of the class groveled and sighed, but Mark took a deep breath. He recognized the patterns. He knew the steps. He wrote down the formulas, calculated the derivatives, and solved the equations one by one.