Leo snorted. “A maths genius. Right.” He flipped a page. Then another. By 3 AM, he’d finished the first chapter without realizing it. The book didn’t talk about formulas or memorization. It talked about seeing numbers. About turning a problem like 47 × 53 into (50-3)(50+3) = 2500 – 9 = 2491. Instantly. Elegantly.

He recalculated. Then again. The final number kept dropping. 12,000 days. 8,000. 3,000.

Below it, in faded red pen:

One rain-lashed Tuesday, a woman in a sequined jacket dragged a waterlogged cardboard box into his lobby. “Unit 37,” she muttered, handing over a key. “Ex-husband’s stuff. Keep it.”

“There’s a book,” Leo would say, pulling out his battered phone. “It’s called Think Like A Maths Genius . You can download the PDF for free. The code still works.”

“Where did you learn that?” she whispered.

The PDF wasn’t a trick. It was a mirror.