The Set of natural number
Notice :
 The set of Natural number
" N " = { o , 1 , 2 , 3 , 4 , …………. }
 The set of Counting numbers " G " = { 1 , 2 , 3 , 4 , 5 , ………. }
 The set of Prime numbers
" P " = { 2 , 3 , 5 , 7 , 11 , ………. }
 The set of Even number
" E " = { o , 2 , 4 , 6 , 8 , …………. }
 The set of Odd number
" O " = { 1 , 3 , 5 , 7 , 9 , …………… }
 N = The set of counting numbers U { O }
 N { O } = The set of counting numbers.
E N , O N
Ex : Put
 ,  , ,
 N
 2 ……
 N
 { 2 } ………
 N
 22.22 ……..

 N
 ………

3
4
 N
 { 55 } ………
 N
 { 2 , o.2 } …….
 N
…….
{1,2,3}


20
4
 N
………
 The set of counting number
{ 2 , 5 , 7 } ……….
Complete :
 O = ……….
 N  E = ……….
 N  O = ………..
E
N
N
E
 E = ………
 O = ……….

 O = ……….
1
Ordering and comparing Natural Numbers
Representing natural numbers on the numbers line:
Ex:
.. .
 X={ 2 , 3 , 6 }
0 1 2
3 4
5 6
... .....
 Y={ 1 , 2 , 3 }
0
1
If X = { 1 , 2 , 3 , 4 , 5 } and
2
3
4
5
6
y = { 5 , 6 , 4 } Re present the
Following sets numbers line :
.
 X y = { 5 }
0
1
2
3
4
5
6
7
 X y = { 1 , 2 , 3 , 5 , 6 , 7 }
... . . .
0
1
2
3
4
5
6
7
8
Express each of the following sets by the listing method and represent
them on the mummer line:
The set of odd numbers : { 1 , 3 , 5 , 7 , ….. }
0
. . . . .
1
2
3
4
5
6
7
8
9
2
The set natural numbers greater than or equal to 4 : { 4 , 5 , 6 , ….. }
0
1
2
3
.....
4
5
6
7
8
9
The set of Prime factors of 30 : { 3 , 2 , 5 }
.. .
0 1 2
3 4
5 6
Write the following sets using the listing method and represent them on
the number line:
X = { a : a  N , where a is between o ,4 }
. ..
{1, 2 ,3}
0 1 2
3 4
5 6
Z={a: a N , a < 6 }
{0 , 1 , 2 , 3 , 4 , 5 }
. .. ...
0
1
2
3
4
5
6
7
Y={a: a N , a ≥ 3 }
. ...
{ 3 , 4 , 5 , ……}
0
M={ a: a N ,
≤ 2 a ≤ 5 }
2
3
4
5
6
7
. ...
{2,3,4, 5}
0
H.W
1
1
2
P5 , P9 ( s,b)
3
4
5
6
7
3