Finding the Prime Numbers by Sieve of Eratosthenes Method

Finding the Prime Numbers by Sieve of Eratosthenes Method

Sieve of Eratosthenes, is a simple method of elimination by which we can easily find the prime numbers upto a given number. This method given by a Greek Mathematician, Eratosthenes of Alexandria, follows some simple steps which are listed below, by which we can find the prime numbers.

 

Step 1: Write the numbers 1 to 100 in ten rows.

Step 2: Cross out 1 because 1 is not a prime.

Step 3: Circle 2 and cross out all multiples of 2. (2, 4, 6, 8, 10, ...)

Step 4: Circle 3 and cross out all multiples of 3. (3, 6, 9, 12, 15, ...)

Step 5: Circle 5 and cross out all multiples of 5. (5, 10, 15, 20, ...)

Step 6: Circle 7 and cross out all multiples of 7. (7, 14, 21, 28, ...)