Prime numbers up to 100

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.
The following are the prime numbers up to 100
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97.

Greek Eratosthenes method to find prime numbers upto 100

1 2 3 4 5 6 7 8 9 10
11 12 13 14 15 16 17 18 19 20
21 22 23 24 25 26 27 28 29 30
31 32 33 34 35 36 37 38 39 40
41 42 43 44 45 46 47 48 49 50
51 52 53 54 55 56 57 58 59 60
61 62 63 64 65 66 67 68 69 70
71 72 73 74 75 76 77 78 79 80
81 82 83 84 85 86 87 88 89 90
91 92 93 94 95 96 97 98 99 100

 

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.

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