Find all the prime numbers within a certain range with this interactive sieve of Eratosthenes. Simply click on any blue number tile, and the program will then as if "remove" (black out) all the multiples of that number. Repeat this process for other "blue" numbers, until in the end, all you have left are primes!
On the right or below you will also see an animation of the sieving or filtering process.
See also this video lesson about the sieve of Eratosthenes.
Click on a blue number tile to remove the multiples of that number (leaving the number itself).