Mammoth Memory

Finding all prime numbers between 1 to 100

To check remember:

 `1` to `100=25` Prime numbers

There are only 25 prime numbers between 1 and 100.

There are 25 prime numbers in 100

Rules

1.  Write all the numbers from 1 to 100 in six columns.

2.  Scratch out the 1 – it's not a prime number.

3.  Circle the ones you do know          

My 

 dog 

bites

several 

  K

G

B

men

2

3

5

7

1

1

1

3

 2

    3

      5

     7

      11

    13

4.  Now draw a straight line down all the even numbers except 2.

5.  Draw a straight line down all the multiples of three except 3.

6.  Draw diagonal lines for all the multiples of 5 and 7 except 5 and 7.

 

This leaves the 25 prime numbers between 1 and 100 which are:

25 prime numbers grid

 

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