Leo clicked. The screen flashed white. Then— pop! —a holographic rabbit with square pupils hopped out of the monitor. It wore a tiny waistcoat covered in multiplication tables.

One rainy Tuesday, his teacher, Mrs. Gálvez, handed out the dreaded workbook: Activados Matemática 3 , from the Puerto de Palos publishing house. “This is your Easter homework,” she said with a smile that smelled like chalk dust and despair. “Complete all 200 problems. No excuses.”

Leo walked outside. The town’s egg hunt was ending. But he didn’t need to find eggs. For the first time, he saw patterns in the petals, symmetry in the fences, and a beautiful fractal in the cracks of the sidewalk.

“Greetings, Leo,” said the rabbit, its whiskers twitching like graph lines. “I am Cálculo, the Keeper of the Empty Page. You typed ‘bastar’— enough . So I’m here to make a deal.”

Cálculo explained: the Activados Matemática 3 book was cursed. Every unsolved problem trapped a small piece of a student’s Easter joy inside a digital prison. “The PDF you wanted doesn’t exist,” the rabbit said. “But the key to freedom does. Solve just three impossible problems—not the whole book—and I will open the Easter Gate.”

On Easter morning, Leo woke up. No golden egg, no fireworks. But on his desk, the Activados Matemática 3 book had turned into a hollow chocolate shell. Inside, instead of problems, there was a single piece of paper: