FAQ

Pick any positive whole number. If it's even, cut it in half. If it's odd, triple it and add one. Repeat. The Collatz conjecture is the (still unproven) observation that no matter which number you start from, you always eventually reach 1. Kollatz turns that pattern into a quick-reflex number game.

You'll see a number in the middle of the screen with four options around it. Only one is the correct next step (even → divide by 2, odd → triple plus one). Pick it before the timer runs out. Reach 1 to clear the stage, then the next stage starts on a bigger number.

The run ends there — Kollatz has no lives or checkpoints mid-run. If you're signed in, your run is saved and you can resume from your best stage next time instead of starting over from Stage 1.

No — you can play as a guest. Signing in with Google lets you save your scores to the leaderboard and resume from your best stage on your next visit, on any device.

Yes. Signing in with the same Google account links your progress and scores everywhere — website or app, it's the same account.

Each correct step is worth points that increase with your current streak, plus a small bonus for answering quickly. The score keeps building for as long as your run continues.