Skip to main content

how to find prime numbers from 1 to 100

By
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.




Comments

Post a Comment

Popular posts from this blog

pythagoras triangle numbers from difference between two adjacent numbers

By
1 2 =1x1=1                           ---->3 2 2 =2x2=4                           ---->5 3 2 =3x3=9                           ---->7 4 2 =4x4= 16                           ----> 9 --->(pythagoras numbers 16+9=25 ==>  4 2 +3 2   = 5 2 ) 5 2 =5x5= 25                           ---->11  6 2 =6x6=36            ...
Post a Comment
Read more

MULTIPLICATION OF TWO CONSECUTIVE NUMBERS

By
If you observe the sum of each digit in the Multiplication of two consectuive no.  pattern repeating:  2 6 3  2 3 6 2 9 9  n X n+1 Multiplication of two consectuive no. Sum of two digits 1X2 2 2 2X3 6 6 3X4 12 3 4X5 20 2 5X6 30 3 6X7 42 6 7X8 56 2 8X9 72 9 9X10 90 9 10X11 110 2 11X12 132 6 12X13 156 3 13X14 182 2 14X15 210 3 15X16 240 6 16X17 272 2 17X18 306 9 18X19 342 9 19X20 380 2 20X21 420 6 21X22 462 3 22X23 506 2 23X24 552 3 24X25 600 6 25X26 650 2 26X27 702 9 27X28 ...
Post a Comment
Read more

product two consecutive odd numbers

By
Product of two consecutive odd numbers : Even numbers are 1,3,5,7,9,11,13,15,17,19,21,23,25,..... Odd  number means when we divide a number with 2,then the remainder is equal to one. Difference between the two odd numbers is 1. Now we will discuss the product of two odd  numbers. Now the product of two even numbers assumed to be 5x7 can be written as (6-1)x(6+1).                              5x7= (6-1)x(6+1) From the above we write general formula as 5x7= (6-1)x(6+1)=6 2 -1 2  =36-1=35 Now we can observe the result as one less than the square number. So now we can observe the following table. Column 1&2 reprecent the adjacent odd numbers. Column 3 represent the product of two adjacent odd numbers. Column 4 represent  the nearest square number. This  will arrive by adding 1 to the product  of two odd ...
Post a Comment
Read more