Eratosthenes
Sieve
Cross out every multiple. What survives is prime. Tap any integer to see how it factors.
Speed
Ready
1 to 50
Press play. Starting at 2, every multiple is crossed out. Numbers that are still standing at the end are prime.
The lattice
Ten per row, so multiples of 2, 5, and 10 fall in columns.
- Open
- Prime
- Composite
- Crossing out
- Unit (1)
Swipe each row to see all ten numbers.