A number is hiding. Its factors will give it away.
A number guessing game with a twist: guess the number from the largest factor it shares with your guess, plus a placement clue for every digit. That's the whole game.
3-digit
Easier mode
Easier mode — Correct Digit mode in the game
Green = right digit, right spot. Orange = right digit, wrong spot. Gray = not in the number.
Harder mode — Count of Correct Digits mode in the game
Positions stay hidden — you only get the totals, as circles.
Both modes give you the GCD — the greatest common divisor between your guess and the hidden number — every turn.
Daily word-guessing games identify a hidden answer through placement clues: each guess reports which letters or colors are in the correct position, which appear elsewhere, and which are absent. These clues describe only how the answer is written.
diviZible, a daily number puzzle, adds a mathematical clue: the greatest common divisor (GCD) of your guess and the hidden number. It describes how the number is built. A GCD of 22 means 22 divides the hidden number, so every number that is not a multiple of 22 is eliminated.
The GCD also rules numbers out. A number that divides your guess but not the GCD cannot divide the hidden number. In both demos the first guess is divisible by 3 and the GCD, 22, is not, so 3 cannot divide the hidden number, and every candidate whose digits add up to a multiple of 3 is eliminated.
Solving the puzzle isn't the end of it. Every hidden number has something worth noticing, and when you crack it, diviZible shows you a card about it — for most numbers, with a small picture. It might be a perfect square, a cube, a power of two or a Fibonacci number. Here is the card for a hidden number of 105:
Ready to try it for real? Play today's puzzle →
Every guess in diviZible comes back with one number, and that number is the greatest common divisor — the largest whole number that divides both your guess and the secret exactly. Guess 12 against a secret of 18 and you'd see 6 come back: both numbers split evenly by 1, 2, 3 and 6, and 6 is the biggest of those.
You might have met this number under a different name before you ever opened diviZible. American classrooms call it the greatest common factor (GCF). British and Commonwealth ones call it the highest common factor (HCF). French speakers call it the PGCD, for plus grand commun diviseur. Whatever you call it, it's the same clue, and the same puzzle.
Two numbers with a GCD of 1 are coprime — they share nothing beyond the trivial factor. In the game, that's the least useful clue you can get back: technically correct, and it tells you almost nothing. Watch for it.
Behind every clue, diviZible runs the Euclidean algorithm — the same method Euclid wrote down around 300 BCE — which is why the game carries the subtitle the Euclidean Puzzle.
The method is one repeated step: divide the larger number by the smaller, keep the remainder, and repeat with the two smaller numbers until the remainder is zero. Whatever's left is the GCD.
Here it is running on the exact guess from the demo above — secret 946, guess 396:
| Step | Division | Remainder |
|---|---|---|
| 1 | 946 = 2 × 396 + 154 | 154 |
| 2 | 396 = 2 × 154 + 88 | 88 |
| 3 | 154 = 1 × 88 + 66 | 66 |
| 4 | 88 = 1 × 66 + 22 | 22 |
| 5 | 66 = 3 × 22 + 0 | 0 — stop |
Last non-zero remainder: 22. That's the number the tile board would have shown you. Check it against the factorizations if you want proof: 946 = 2 × 11 × 43 and 396 = 2 × 2 × 3 × 3 × 11 — the shared factors are 2 and 11, and 2 × 11 = 22.
Five steps, no factoring required. You don't need to see this math to play well — but knowing it's running under the hood is part of what makes a big GCD feel like a real discovery instead of a random number.
The daily puzzle is the same for everyone. Euclidean Mission lets you set your own: pick the hidden number, and diviZible gives you a short 5-character code and a link to share. Whoever opens it plays exactly that puzzle.
Send one to a friend, set a challenge for the family, or give a class a number chosen to practice a specific skill: divisibility rules, factoring, or calculating GCDs. No account is needed on either end, and nothing about how anyone did is sent back to you.
In the game, tap the compass icon to create a Mission or join one.
No accounts, no logins, no cookies, no tracking and no ads matters just as much to a teacher as it does to a puzzle player who doesn't want to sign up for anything — nothing to collect, no permission slips, no IT review. A student opens a link and plays, same as anyone else.
If you do want to run it as a warm-up: one shared puzzle a day means the whole room is solving the same problem, so a projected board works well — take guesses from the class, and make them justify each one before it goes in. Four daily variants (three-digit and four-digit, easier and harder) give you a difficulty ladder if the group's mixed-ability, and the post-game analysis breaks down which guesses could never have won and why.
To set your own puzzle for the class instead of the daily one, use Euclidean Mission.
Using it with a class? We'd like to hear what works and what doesn't — get in touch.
Yes. GCD, GCF (greatest common factor), HCF (highest common factor) and the French PGCD all name the same quantity: the largest whole number dividing both of two numbers. The name varies by country and curriculum, not the mathematics.
If you have played Wordle, the color clues will look familiar: green for the right digit in the right place, orange for the right digit somewhere else, gray for a digit that is not in the number. The difference is what diviZible adds on top. Those clues describe how the answer is written; diviZible also tells you how it is built, by giving you the greatest common divisor your guess shares with the hidden number. That is a second, independent kind of clue, so every guess pays you twice. The answer is a three- or four-digit number rather than a word, there are four puzzles a day rather than one, and the harder mode hides the positions entirely and gives you only the totals, closer to Mastermind.
The Euclidean algorithm. Divide the larger by the smaller, keep the remainder, repeat with the two smaller numbers, and stop when the remainder reaches zero. The last non-zero remainder is the GCD. It is far quicker than listing factors, and it is what computers use.
Because the clue at the heart of the game is the greatest common divisor, and the classical way to compute one is the Euclidean algorithm, described by Euclid around 300 BCE in Book VII of the Elements. Every guess you make sets up a small instance of the problem Euclid solved.
No. There are no accounts and no sign-up. The game runs entirely in your browser, and your guesses and statistics are stored only on your own device.
Yes — free, with no ads and no paid tier.
Easier mode — diviZible calls it Correct Digit mode — colors each digit of your guess: green for the right digit in the right place, orange for the right digit in the wrong place, gray for a digit not in the number. Harder mode — Count of Correct Digits mode — hides the positions and gives you only the totals, Mastermind-style. Both modes give you the GCD every time.
Four: three-digit and four-digit numbers, each in easier and harder mode. Everyone playing on a given day gets the same puzzles.
Yes. Share result copies a Wordle-style grid of colored squares to your clipboard — one row per guess, showing only the placement colors, so the number of rows is your try count. The hidden number never appears in it, so posting it doesn't spoil the puzzle for anyone who hasn't played yet.
Yes. Post-puzzle analysis breaks the game down guess by guess: how many candidates were still possible after each one, and — tap any guess — exactly why it ruled out the ones it did. It's a quick way to tell a guess that felt clever from one that actually did the work.
Yes — that's Euclidean Mission. Pick the hidden number and diviZible gives you a short 5-character code and link to share with students. They open it and play that exact puzzle; nothing about their results is sent back to you, keeping the same no-tracking policy as the rest of the game.