Okay, picture this: we rig a harmless classroom prank that doubles as a spontaneous lesson—like a pop‑up quiz hidden inside a magic trick. The surprise turns the whole room into a math mystery. Ready to brainstorm?

Sounds epic—let’s aim for about 12 to 15 kids, the sweet spot for a tight‑knit treasure vibe. For the magic prop, I’d go with a set of “mystery‑card” envelopes that look like ordinary postcards but each opens to reveal a tiny chalk‑board with the clue. The envelopes hide a simple trick: a small, reversible “invisible ink” pen—kids write a secret number in the dark, and when the classroom lights flicker the numbers glow, giving the final “aha” reveal. Stickers, a shiny coin prize, and a flash of that invisible ink glow is enough to keep the brain buzzing. Ready to start the hunt?