A number puzzle where matching a shared prime factor transforms the gems — and one good move can set off a chain.
The whole first island, free. Works with a mouse or a finger. Out now on Google Play and the App Store.
On a computer? Scan to get Factor Gems on your phone.
Watch it in action
Match what numbers share
Gems carry numbers. Line up four or more that share a prime factor and they do not simply vanish — each one is divided by it.
Line up four
2, 6, 10 and 14 look different, but every one of them is divisible by 2.
Peel the factor
Divide them all by 2. The first gem reaches 1 and leaves the board; the others become 3, 5 and 7.
Start a chain
New gems fall into place and new lines appear. One good move can set off a cascade across the board.
The Gem Workshop
Cleared levels pay out gems. Merge two gems into their product, split a gem into its factors, or nudge it with rare +1 and −1 gems — and fill the Number Atlas with all 256 numbers.
Did you know? A piano has 88 keys. Every gem you collect unlocks a short, true story about its number, from history, science, geography and more.
Show off your finds
Every cleared level and every new gem can become a picture card to share with friends — the gem, its prime factors and its story on a sticky note.
Myriora Maths: free lessons that explain the why
Short animated maths lessons for children aged 5 to 11, from counting to algebra, plus every type of 11+ puzzle. Each lesson shows why a rule works, the common mistake to avoid, and one idea to try at home.
Calculamancer
A card game where the maths is the magic. Add or subtract cards to match the last play, link equal values into long chains, charge your character's spell and race to empty your hand. For two to four players: against the computer, or with friends on the same Wi-Fi.
Unlock once, then just play
A game you unlock once has no reason to interrupt you, no reason to make a level artificially hard so that a bundle of moves looks attractive, and no reason to know anything about you.
No ads
Nothing interrupts a puzzle, and there is nothing to buy beyond the one unlock.
No accounts
No sign-up, no login, and progress stays on your own device.
Nothing collected
No analytics or tracking in the games or on this site. Privacy policy.