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Home >> Numbers >> Sieve of Eratosthenes >>

## Sieve of Eratosthenes

 Numbers and Numerals Composite Numbers Prime Numbers Facts (Prime Numbers) Even Numbers Odd Numbers Natural Numbers Whole Numbers Predecessor Number Successor Number Number Expansion Number Comparison Literal Numbers Roman Numbers Coprime Numbers Perfect Numbers Multiplication Properties of Numbers Order of Numbers Sieve of Eratosthenes Number line Square Numbers Shortcut Method of Numbers Cube Numbers Real Numbers

Explanation
In Third Century B.C. a Greek Mathmatician " Eratosthenes " developed a table to List all the Prime Numbers and Composite Numbers between 1 to 100. This method is known as " Sieve of Eratosthenes"
The Table developed by him is as:-

 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 Steps to be followed are as:-
Step 1 = Strike Out 1 because 1 is neither a Prime Number nor a Composite Number.
Step 2 = Write 2 in bold.
Step 3 = Strike Out all the Multiple of 2 other than itself. e.g. 2, 4, 6, 8, 10, 12 ........and so on till 100.
Step 4 = After Step 3, the next non-strike number you will find is 3. Write 3 in bold.
Step 5 = Strike Out all the Multiple of 3 other than itself. e.g. 9, 15, 21, 27, ........and so on till 100.
Step 6 = After Step 5, the next non-strike number you will find is 5. Write 5 in bold.
Step 7 = Strike Out all the Multiple of 5 other than itself. e.g. 25, 35, 55, ........and so on till 100.
Step 8 = After Step 7, the next non-strike number you will find is 7. Write 7 in bold.
Step 9 = Strike Out all the Multiple of 7 other than itself.
Step 10 = Continue this process, untill all the numbers in the table are either Strike out or written in Bold.
Step 11 = All the Strike Out Numbers are Composite Numbers (except 1).
Step 12 = All those numbers which are written in Bold are Prime Numbers.