Keep Prime Numbers
Played 2 times.
About Keep Prime Numbers
Here is a number puzzle that asks one question over and over: prime or composite? A set of numbered blocks fills the screen, and your job is to get rid of the composite numbers while the primes stay in place.
Clicking or tapping the leftover block sends composite numbers off the screen, so spotting which values divide evenly is the skill that matters. It is a handy way to refresh your memory of primes in a low-pressure setting, and it suits both students and curious adults. It runs free in your browser on a computer or phone.
Game details
| Genre | Racing |
|---|---|
| Controls | Mouse or touch |
| Platform | Browser, phone and tablet |
| Cost | Free, no download |
| Screen | 800 x 480 px |
How to play Keep Prime Numbers
- Look at the numbered blocks and decide which are composite.
- Press the spare block to release a composite number.
- Keep every prime number in place.
- Clear all the composite blocks to finish the puzzle.
Tips for Keep Prime Numbers
- Learn the first few primes, such as 2, 3, 5, 7, 11 and 13, so you can spot them quickly.
- Even numbers other than 2 are always composite, so you can drop them straight away.
- Check a number by testing small divisors before you tap, because a wrong drop loses a prime.
Frequently asked questions
Is Keep Prime Numbers free?
Yes. Keep Prime Numbers is free to play in your browser with no download and no sign-up.
How do I play Keep Prime Numbers on a phone?
Touch or tap the spare block to release composite numbers. On a computer you click with the mouse instead.
What is the goal of Keep Prime Numbers?
Clear out every block holding a composite number while the primes stay on screen, using clicks or taps on the spare block.
More to play: Racing games · Educational games · Math games
Categories Tags Comments
