How we worked it out
Updated as you change the numbers.
- Trial division up to the square root tests one number; the sieve of Eratosthenes lists all primes in a range.
Method and assumptions
A prime has exactly two divisors, 1 and itself. There are 25 primes below 100 and 664,579 below ten million.
Questions
How many primes are there below 100?
25.
Sources
Method and figures checked on . Every worked answer on this page is covered by an automated test. Found a mistake? Tell us.