In this page we are going to see the list of prime numbers up to 100 .
- Prime numbers are positive numbers greater than 1 .
- A number to be prime number it must be non-zero whole number.
- Prime numbers are the numbers that cannot be divided by any number except themselves and one.
- Prime numbers have only two factors.
- The two factors of prime numbers are one and the number itself.
- The way of finding the prime numbers is called integer factorization, or prime factorization.
Greek Eratosthenes method to find prime numbers upto 100
The Greek Eratosthenes formed a technique to find out these prime numbers, although it only worked over a restricted range:
- Write out the numbers from 1 to 100 in as shown above.
- Cross out the number 1, because all primes are greater than 1.
- Number 2 is a prime, so we can keep 2 as it is, and we cross out all the numbers that are multiplies of 2. (like 4,6,8,10 ….)
- Number 3 is also a prime number, so we keep 3 as it is and we cross out all the numbers that are the multiples of 3.( like 3,6,9,…….)
- The next number left is 5 , so we keep 5 as it is and we cross out all the numbers that are the multiples of 5 ( like 10 ,15, 20, 25…..)
- At last the number left in the first row is number 7, now we keep 7 as it is and we cross out all the numbers that are the multiples of 7 ( like 14, 21, 28 ……)
- Now all of the remaining numbers in the table are prime numbers.
Some facts about prime numbers
- The only even prime number is 2 and remaining even numbers can be divided by 2 so it cant be prime number.
- No prime number greater than 5 ends in a 5.Since any number greater than 5 that ends in a 5 can be divided by 5 so it cant be prime number.
- Zero and 1 are not considered prime numbers.
- Except for 0 and 1, a number is called as either a prime number or a composite number.