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how to find prime numbers from 1 to 100

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In all competitive exams questions on prime numbers are asked. Prime numbers are important when you are concerned series questions.
Now we will see how to write prime numbers.
Multiple of 2: 2,4,6,8,10,12,14,16,18,20,22,24,26,28,30,32,34,36,38,40,42,42,44,46,48,50,52,54,56,58,60,62,64,66,68,70,72,74,76,78,80,82,84,86,88,90,92,94,96,98,100
Multiple of 3:3,6,9,12,15,18,21,24,27,30,33,36,39,42,45,48,51,54,57,60,63,66,69,72,75,78,81,84,87,90,93,96,99
Multiple of 4: 4,8,12,16,20,24,28,32,36,40,44,48,52,56,60,64,68,72,76,80,84,88,92,96,100
Multiple of 5: 5,10,15,20,25,30,35,40,45,50,55,60,65,70,75,80,85,90,95,100
Multiple of 6: 6,12,18,24,30,36,42,48,54,60,66,72,78,84,90,96
Multiple of 7: 7,14,21,28,35,42,49,56,63,70,77,84,91,98
Multiple of 8: 8,16,24,32,40,48,56,64,72,80,88,94
Multiple of 9:9,18,27,36,45,54,63,72,81,90,99
Multiple of 10: 10,20,30,40,50,60,70,80,90,100
Multiple of 11: 11,22,33,44,55,66,77,88,99


Now WE will write the number from 1 to 100

e

So now will eliminate all the multiple numbers from 2 to 11 from the above table except 2,3,5,7,11.
After eliminate the numbers remaining numbers are  prime numbers.shown by  colour.



By observing the table we will know that 25 prime numbers are existing from 1 to 100.
Important points to note are:
1.number 1 is not a prime number
2.number 2 is a even prime number.
Now we will eliminate the numbers other than prime numbers.




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