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RATIONAL
NUMBERS
 DEFINITION OF RATIONAL NUMBERS
 COMPARISON OF RATIONAL AND IRRATIONAL
NUMBERS
 PROPERTIES OF RATIONAL NUMBERS
 OPERATIONS ON RATIONAL NUMBERS
 ROLE OF  0  and  1
 NEGATIVE OF RATIONAL NUMBERS
 RECIPROCAL OF RATIONAL NUMBERS
 REPRESENTATION OF RATIONAL NUMBERS ON
NUMBER LINE
 RATIONAL NUMBERS BETWEEN ANY TWO
RATIONAL NUMBERS
Rational number class 8th
Rational number class 8th
 Def:- Rational numbers :- The numbers are
of the form
i)p/q form
ii)p,q 贈 Z
iii)q 0
 Rational numbers are indicated by capital  Q
(QUOZIENTE---ITALIAN---QUOTIENT)
 CLOSURE PROPERTY:-If a , b are any
two rational numbers then they are under
1. ADDITION a+bQ--------- CLOSED
2. SUBTRACTION a-bQ ---------CLOSED
3. MULTIPLICATION axbQ---------CLOSED
4. DIVISION a歎bQ -------- CLOSED
If a , b are any two rational numbers then they
are under
1. ADDITION a+b=b+a-------- TRUE
2. SUBTRACTION a-bb-a ------ FALSE
3. MULTIPLICATION axb=bxa-------TRUE
4. DIVISION a歎bb歎a ------------FALSE
 If a, b, c are any three rational numbers then
they are under
1. ADDITION (a+b)+c=a+(b+c)----- TRUE
2. SUBTRACTION (a-b)-ca-(b-c) --- FALSE
3. MULTIPLICATION (axb)xc=ax(bxc) --TRUE
4. DIVISION (a歎b)歎ca歎(b歎c) --------FALSE
 When we multiply the given number by the
other number the result is 1.,then one of
the number is the reciprocal of the other
number.
 then the multiplied number is called
multiplicative inverse
 Here  1 is called multiplicative identity of
rational numbers.

When a rational number is multiplied with the
reciprocal
or
 multiplicative inverse of its own,
result will be one (1)
 i.e.
 x/y  y/x = 1.
Example: 2/7  7/2 = 1; etc.
 When any rational number is added to zero
(0),
 then it will result in the same rational
number
 i.e.
 x/y + 0 = x/y.
Zero is called the identity for the addition of
rational numbers.
Example:
 2/3 + 0 = 2/3;
 -5/7 + 0 = -5/7; etc.
 When any rational number is multiplied with
one (1),
 then
 it will result in the same rational number
 i.e. x/y  1 = x/y.
One is called the multiplicative identity for
rational numbers.
Example: 2/7  1 = 2/7;
 -8/3  1 = -8/3; etc.
 When we add any number to the given
number the result is 0.
 Adding number is called NEGATIVE OF A
GIVEN RATIONAL NUMBER.
 Then the added number is called a additive
inverse .
 Here 0  is called additive identity of rational
numbers.
 ) When a rational number is added to the
negative
or
 additive inverse of its own,
 result will be zero (0)
i.e.
x/y + (-y/x) = 0.
Example: 2/7 + (-7/2) = 0; etc.
:
Closure Property
Associative Property
Commutative Property
Distributive Property
Identity Property
Inverse property
Property Addition Multiplication Subtraction Division
1.
Commutative
Property
x + y = y+ x x  y = y  x x  y  y  x x 歎 y  y 歎 x
2.
Associative
Property
x + (y + z) = (x + y) +z x  (y  z) = (x  y)  z (x  y)  z  x  (y  z) (x 歎 y) 歎 z  x 歎 (y 歎 z)
3.
Identity
Property
x + 0 = x =0 + x x  1 = x = 1  x x  0 = x  0  x x 歎 1 = x  1 歎 x
4.
Closure
Property
x + y  Q x  y  Q x  y  Q x 歎 y  Q
5.
Distributive
Property
x  (y + z) = x  y + x z
x  (y  z) = x  y  x  z
 Rational numbers can also be represented on
the Number line
 Rational numbers can also be represented on the Number line
example of 4/9
Step (1)
In a rational number, the numeral below the bar, i.e., the
denominator, tells the number of equal parts into which the first
unit has been divided. The numeral above the bar i.e.
the numerator, tells how many of these parts are considered
So in this particular example, we need to divide the first unit into 9
parts and we need to move to the 4th part
 Step (2) Draw the straight line. Divide the
first unit into equal parts equal to the
denominator of the rational number. And
then mark each equal part to the right of the
line and reach the desired number

More Related Content

Rational number class 8th

  • 2. DEFINITION OF RATIONAL NUMBERS COMPARISON OF RATIONAL AND IRRATIONAL NUMBERS PROPERTIES OF RATIONAL NUMBERS OPERATIONS ON RATIONAL NUMBERS ROLE OF 0 and 1 NEGATIVE OF RATIONAL NUMBERS RECIPROCAL OF RATIONAL NUMBERS REPRESENTATION OF RATIONAL NUMBERS ON NUMBER LINE RATIONAL NUMBERS BETWEEN ANY TWO RATIONAL NUMBERS
  • 5. Def:- Rational numbers :- The numbers are of the form i)p/q form ii)p,q 贈 Z iii)q 0 Rational numbers are indicated by capital Q (QUOZIENTE---ITALIAN---QUOTIENT)
  • 6. CLOSURE PROPERTY:-If a , b are any two rational numbers then they are under 1. ADDITION a+bQ--------- CLOSED 2. SUBTRACTION a-bQ ---------CLOSED 3. MULTIPLICATION axbQ---------CLOSED 4. DIVISION a歎bQ -------- CLOSED
  • 7. If a , b are any two rational numbers then they are under 1. ADDITION a+b=b+a-------- TRUE 2. SUBTRACTION a-bb-a ------ FALSE 3. MULTIPLICATION axb=bxa-------TRUE 4. DIVISION a歎bb歎a ------------FALSE
  • 8. If a, b, c are any three rational numbers then they are under 1. ADDITION (a+b)+c=a+(b+c)----- TRUE 2. SUBTRACTION (a-b)-ca-(b-c) --- FALSE 3. MULTIPLICATION (axb)xc=ax(bxc) --TRUE 4. DIVISION (a歎b)歎ca歎(b歎c) --------FALSE
  • 9. When we multiply the given number by the other number the result is 1.,then one of the number is the reciprocal of the other number. then the multiplied number is called multiplicative inverse Here 1 is called multiplicative identity of rational numbers.
  • 10. When a rational number is multiplied with the reciprocal or multiplicative inverse of its own, result will be one (1) i.e. x/y y/x = 1. Example: 2/7 7/2 = 1; etc.
  • 11. When any rational number is added to zero (0), then it will result in the same rational number i.e. x/y + 0 = x/y. Zero is called the identity for the addition of rational numbers. Example: 2/3 + 0 = 2/3; -5/7 + 0 = -5/7; etc.
  • 12. When any rational number is multiplied with one (1), then it will result in the same rational number i.e. x/y 1 = x/y. One is called the multiplicative identity for rational numbers. Example: 2/7 1 = 2/7; -8/3 1 = -8/3; etc.
  • 13. When we add any number to the given number the result is 0. Adding number is called NEGATIVE OF A GIVEN RATIONAL NUMBER. Then the added number is called a additive inverse . Here 0 is called additive identity of rational numbers.
  • 14. ) When a rational number is added to the negative or additive inverse of its own, result will be zero (0) i.e. x/y + (-y/x) = 0. Example: 2/7 + (-7/2) = 0; etc.
  • 15. : Closure Property Associative Property Commutative Property Distributive Property Identity Property Inverse property
  • 16. Property Addition Multiplication Subtraction Division 1. Commutative Property x + y = y+ x x y = y x x y y x x 歎 y y 歎 x 2. Associative Property x + (y + z) = (x + y) +z x (y z) = (x y) z (x y) z x (y z) (x 歎 y) 歎 z x 歎 (y 歎 z) 3. Identity Property x + 0 = x =0 + x x 1 = x = 1 x x 0 = x 0 x x 歎 1 = x 1 歎 x 4. Closure Property x + y Q x y Q x y Q x 歎 y Q 5. Distributive Property x (y + z) = x y + x z x (y z) = x y x z
  • 17. Rational numbers can also be represented on the Number line
  • 18. Rational numbers can also be represented on the Number line example of 4/9 Step (1) In a rational number, the numeral below the bar, i.e., the denominator, tells the number of equal parts into which the first unit has been divided. The numeral above the bar i.e. the numerator, tells how many of these parts are considered So in this particular example, we need to divide the first unit into 9 parts and we need to move to the 4th part
  • 19. Step (2) Draw the straight line. Divide the first unit into equal parts equal to the denominator of the rational number. And then mark each equal part to the right of the line and reach the desired number