SlideShare a Scribd company logo
MATHE MATICS
Std. VIII
A TEXT BOOK OF
MATHEMATICS
STD : VIII
MATHEMATICS
DIGITAL TEXT BOOK
Std. VIII
Anchulekshmi A R
B.Ed Mathematics
Reg.No. 18014350002
CONTENTS
Chapter I
Equations
1. Addition and Subtraction
2. Multiplication and Division
3. Method ofAlgebra
4. Different Problems
1. Polygons
Chapter II
Polygons
2. Sum of the angles
3. External angles
4. Unchanging sum
5. Regular Polygons
Chapter 1
EQUATIONS
Equations are algebraic sentences denoting equality
of numbers
Addition and Subtraction
i. Addition of numbers
Eg: 40 + 3 = 43
50 + 3 = 53
H. Subtraction of Numbers
Eg: 40 - 3 = 37
50 - 3 = 47
Problems related to Addition and Subtraction of Numbers
Eg: Rajan said "if 6 more marks were granted. My
marks in Maths would be 100." Howmany marks
did he get?
Ans : It will become 100 if 6 more added. So his marks is
6 less than 100.
100 - 6 = 94. This is Rajans Marks.
Equations 1
Multiplication and Division
i. Multiplication of Numbers
Eg: 40 x 3 = 120
22 x 3 = 66
ii. Division of Numbers
Eg: 125 + 5 = 25
42+2=21
Problems related to Multiplication and Division of
Numbers
Eg: A number multiplied by 12 gIves 756. Which
number was multiplied?
Ans: 756 + 12 = 63
Method of Algebra
It is easy to solve all the problems of numbers using
algebra.
The unknown number or variable ofthe equation is x.
Then to find x, in all cases we used the method of inverse
operation in charge subtraction to addition, change
Equations 2
... multiplication to division and change division to
~.
tnlltiplication.
The formulas are
if x+a= b, x =b - a
if x-a = b, x=b+a
b
if ax=b X= -, a
if ~=b , x=bxa
a
if ax+b = c, ax = c-b
c-b
x=--
a
To Recollect
x + x = 2x
x + 2x = 3x
2x + 3x = 5x
5x - x = 4x
2x - x = x
7x - 5x = 2x
2x + 1 = 2x + 1 it self
Equations 3
Different Problems
Eg: When 10 was added to 2 times a number, we get 4
times the number. What is the number?
Ans: Let the number be x
2x+10 = 4x
There is variable on both sides ofthe equal to. sign in
this equation.
Subtract 2x from both sides of the equal to sign
Equations
2x + 10 - 2x = 4x - 2x
10 = 2x
2x = 10
10
x=-=5
2
4
Chapter 2
POLYGONS
Polygons is the common name given to shapes with
three or more sides.
Eg:6D
Sum of the Angles
The sum ofthe angles of a polygon of n sides is
(n-2) x 1800
The sum of the angles of a polygon is always a
multiple of 180.
Eg: What is the sum ofthe angles ofa polygon of52 sides.
Ans : Sum ofthe angles
= (n-2) x 1800
= (52 - 2) x 1800
=50x180
= 90000
External Angles
If one side of a triangle is extended. We get an exter-
nal.angle.
Polygons 5
Co
In triangle ABC, side BC is extended to D.
LACD is an external angle at corner C
LACB is the internal angle at corner C.
Since these two angles form a linear pair.
LACD + LACB = 1800
or
LACD = 1800
- LACB
Unchanging Sum
D
In i1ABC, the sum of the internal angle and external
angle at corner A = 1800
(linear pair).
In i1ABC, the sum of the internal angle and external
Polygons 6
angle at comer B = 1800
(Linear pair)
In L1ABC, the sum of the internal angle and external
angle at comer C = 1800
(linear pair)
Sum of the three internal angles and three external
angles of L1ABC = 180x3 = 5400
But sum ofthe internal angles = 1800
So sum of the angles external
= 540 - 180 = 3600
In any triangle, the sum ofthe external
angles is 360°.
Now let us examine the case in a quadrilateral.
Sum of the internal angle and external angle at
A = 1800
Sum of the internal angle and external angle at all
four corners = 180 x 4 = 7200
A ------L....LJ
B
Polygons 7
But sum of the internal angles of a quadrilateral is
360°.
So sum ofthe external angles of a quadrilateral
= 720 - 360
= 360°
In the same way examine the sum ofthe external angles
of a pentagon, hexagone, etc. Always we get it as 360°.
Sum ofthe external angles ofany
polygon is 360°.
Eg: The angles of 18 sided polygon are equal. What is the
measure of each external angle?
Ans: Sum ofthe external angles ofthe polygon with
18 sides = 360°.
Since the angles are equal, external angles are
also equal.
Measure of each external angle = 360 = 200
18
Regular Polygons
Polygons with all sides equal and all angles equal are
called regular polygons.
Polygons 8
MATHE MATICS
Std. VIII
A TEXT BOOK OF
MATHEMATICS
STD : VIII

More Related Content

What's hot

Class 10 Cbse Maths Sample Paper Term 2 Model 3
Class 10 Cbse Maths Sample Paper Term 2 Model 3Class 10 Cbse Maths Sample Paper Term 2 Model 3
Class 10 Cbse Maths Sample Paper Term 2 Model 3
Sunaina Rawat
 
Math hssc-i-bc
Math hssc-i-bcMath hssc-i-bc
Obj. 34 Ratio and Proportion
Obj. 34 Ratio and ProportionObj. 34 Ratio and Proportion
Obj. 34 Ratio and Proportion
smiller5
 
Squares & square roots - class 8th
Squares & square roots -  class 8th Squares & square roots -  class 8th
Squares & square roots - class 8th
sanarajar786
 
8 2 Triangle Sum Theorem
8 2 Triangle Sum Theorem8 2 Triangle Sum Theorem
8 2 Triangle Sum Theorem
taco40
 
MATHEMATICS MODEL QUESTION PAPER FOR CBSE CLASS 10
MATHEMATICS MODEL QUESTION PAPER FOR CBSE CLASS 10MATHEMATICS MODEL QUESTION PAPER FOR CBSE CLASS 10
MATHEMATICS MODEL QUESTION PAPER FOR CBSE CLASS 10
Bagalkot
 
Mathematics form 1&2 short simple notes By Kelvin 2H/2017
Mathematics form 1&2 short simple notes By Kelvin 2H/2017Mathematics form 1&2 short simple notes By Kelvin 2H/2017
Mathematics form 1&2 short simple notes By Kelvin 2H/2017
KelvinSmart2
 
Properties of triangles
Properties of trianglesProperties of triangles
Properties of triangles
Dreams4school
 
8.5 Polar Form
8.5 Polar Form8.5 Polar Form
8.5 Polar Form
smiller5
 
May 14, 2014
May 14, 2014May 14, 2014
May 14, 2014khyps13
 
8.1 find angle measures in polygons
8.1 find angle measures in polygons8.1 find angle measures in polygons
8.1 find angle measures in polygonsdetwilerr
 
5.13.2 Area of Regular Polygons and Composite Shapes
5.13.2 Area of Regular Polygons and Composite Shapes5.13.2 Area of Regular Polygons and Composite Shapes
5.13.2 Area of Regular Polygons and Composite Shapes
smiller5
 
Ac1.3hMorePracticeProblems
Ac1.3hMorePracticeProblemsAc1.3hMorePracticeProblems
Ac1.3hMorePracticeProblems
Wissahickon High School, Ambler, PA 19002
 
Chapter 1 lines and angles ii [compatibility mode]
Chapter 1   lines and angles ii [compatibility mode]Chapter 1   lines and angles ii [compatibility mode]
Chapter 1 lines and angles ii [compatibility mode]
Khusaini Majid
 

What's hot (16)

Ratio and proportion
Ratio and proportionRatio and proportion
Ratio and proportion
 
Class 10 Cbse Maths Sample Paper Term 2 Model 3
Class 10 Cbse Maths Sample Paper Term 2 Model 3Class 10 Cbse Maths Sample Paper Term 2 Model 3
Class 10 Cbse Maths Sample Paper Term 2 Model 3
 
Math hssc-i-bc
Math hssc-i-bcMath hssc-i-bc
Math hssc-i-bc
 
April 1
April 1April 1
April 1
 
Obj. 34 Ratio and Proportion
Obj. 34 Ratio and ProportionObj. 34 Ratio and Proportion
Obj. 34 Ratio and Proportion
 
Squares & square roots - class 8th
Squares & square roots -  class 8th Squares & square roots -  class 8th
Squares & square roots - class 8th
 
8 2 Triangle Sum Theorem
8 2 Triangle Sum Theorem8 2 Triangle Sum Theorem
8 2 Triangle Sum Theorem
 
MATHEMATICS MODEL QUESTION PAPER FOR CBSE CLASS 10
MATHEMATICS MODEL QUESTION PAPER FOR CBSE CLASS 10MATHEMATICS MODEL QUESTION PAPER FOR CBSE CLASS 10
MATHEMATICS MODEL QUESTION PAPER FOR CBSE CLASS 10
 
Mathematics form 1&2 short simple notes By Kelvin 2H/2017
Mathematics form 1&2 short simple notes By Kelvin 2H/2017Mathematics form 1&2 short simple notes By Kelvin 2H/2017
Mathematics form 1&2 short simple notes By Kelvin 2H/2017
 
Properties of triangles
Properties of trianglesProperties of triangles
Properties of triangles
 
8.5 Polar Form
8.5 Polar Form8.5 Polar Form
8.5 Polar Form
 
May 14, 2014
May 14, 2014May 14, 2014
May 14, 2014
 
8.1 find angle measures in polygons
8.1 find angle measures in polygons8.1 find angle measures in polygons
8.1 find angle measures in polygons
 
5.13.2 Area of Regular Polygons and Composite Shapes
5.13.2 Area of Regular Polygons and Composite Shapes5.13.2 Area of Regular Polygons and Composite Shapes
5.13.2 Area of Regular Polygons and Composite Shapes
 
Ac1.3hMorePracticeProblems
Ac1.3hMorePracticeProblemsAc1.3hMorePracticeProblems
Ac1.3hMorePracticeProblems
 
Chapter 1 lines and angles ii [compatibility mode]
Chapter 1   lines and angles ii [compatibility mode]Chapter 1   lines and angles ii [compatibility mode]
Chapter 1 lines and angles ii [compatibility mode]
 

Similar to Digital text book

Digital text book
Digital text book Digital text book
Digital text book
antonyge68
 
DIGITAL TEXT BOOK
 DIGITAL TEXT BOOK DIGITAL TEXT BOOK
DIGITAL TEXT BOOK
antonyge68
 
Digital text
Digital textDigital text
Digital text
archa1989
 
Digital text book
Digital text bookDigital text book
Digital text book
laluls212
 
Module 4 geometry of shape and size
Module 4  geometry of shape and sizeModule 4  geometry of shape and size
Module 4 geometry of shape and size
dionesioable
 
Pdm presentation
Pdm presentationPdm presentation
Pdm presentation
Budiana Putu
 
POTENCIAS Y RAÍCES DE NÚMEROS COMPLEJOS-LAPTOP-3AN2F8N2.pptx
POTENCIAS Y RAÍCES DE NÚMEROS COMPLEJOS-LAPTOP-3AN2F8N2.pptxPOTENCIAS Y RAÍCES DE NÚMEROS COMPLEJOS-LAPTOP-3AN2F8N2.pptx
POTENCIAS Y RAÍCES DE NÚMEROS COMPLEJOS-LAPTOP-3AN2F8N2.pptx
TejedaGarcaAngelBala
 
Chapter 7.pptx
Chapter 7.pptxChapter 7.pptx
Chapter 7.pptx
Happy Ladher
 
imc-2018-s.pdf
imc-2018-s.pdfimc-2018-s.pdf
imc-2018-s.pdf
bhartanto5
 
Chapter1.integer s.y.b.c.s
Chapter1.integer s.y.b.c.sChapter1.integer s.y.b.c.s
Chapter1.integer s.y.b.c.s
vidyabhoge1
 
Interior-and-Exterior-Angles-of-Polygons.ppt
Interior-and-Exterior-Angles-of-Polygons.pptInterior-and-Exterior-Angles-of-Polygons.ppt
Interior-and-Exterior-Angles-of-Polygons.ppt
JeraldelEncepto
 
Question bank -xi (hots)
Question bank -xi (hots)Question bank -xi (hots)
Question bank -xi (hots)
indu psthakur
 
Lines and angles
Lines and anglesLines and angles
Lines and anglesandylouis1
 
FS Maths Level 2 - April 8, 2023 (Angles, Circles, 2D shapes area and perimet...
FS Maths Level 2 - April 8, 2023 (Angles, Circles, 2D shapes area and perimet...FS Maths Level 2 - April 8, 2023 (Angles, Circles, 2D shapes area and perimet...
FS Maths Level 2 - April 8, 2023 (Angles, Circles, 2D shapes area and perimet...
LeadAcademy3
 
FS Maths Level 2 – May 13, 2023 (Angles, Circles, 2D shapes (area and perimet...
FS Maths Level 2 – May 13, 2023 (Angles, Circles, 2D shapes (area and perimet...FS Maths Level 2 – May 13, 2023 (Angles, Circles, 2D shapes (area and perimet...
FS Maths Level 2 – May 13, 2023 (Angles, Circles, 2D shapes (area and perimet...
LeadAcademy3
 
FS Maths Level 2 - April 8, 2023 (Angles, Circles, 2D shapes area and perimet...
FS Maths Level 2 - April 8, 2023 (Angles, Circles, 2D shapes area and perimet...FS Maths Level 2 - April 8, 2023 (Angles, Circles, 2D shapes area and perimet...
FS Maths Level 2 - April 8, 2023 (Angles, Circles, 2D shapes area and perimet...
LeadAcademy3
 
Mathematics TAKS Exit Level Review
Mathematics TAKS Exit Level ReviewMathematics TAKS Exit Level Review
Mathematics TAKS Exit Level Review
guest3f17823
 
M103-ADEPT 8.pptx
M103-ADEPT 8.pptxM103-ADEPT 8.pptx
M103-ADEPT 8.pptx
Marjorie Malveda
 
Ppt Understanding Quadrilaterals (Module 1) Class VIII.pptx
Ppt Understanding Quadrilaterals (Module 1) Class VIII.pptxPpt Understanding Quadrilaterals (Module 1) Class VIII.pptx
Ppt Understanding Quadrilaterals (Module 1) Class VIII.pptx
Savidha Nair
 
Geometric series
Geometric seriesGeometric series
Geometric series
JJkedst
 

Similar to Digital text book (20)

Digital text book
Digital text book Digital text book
Digital text book
 
DIGITAL TEXT BOOK
 DIGITAL TEXT BOOK DIGITAL TEXT BOOK
DIGITAL TEXT BOOK
 
Digital text
Digital textDigital text
Digital text
 
Digital text book
Digital text bookDigital text book
Digital text book
 
Module 4 geometry of shape and size
Module 4  geometry of shape and sizeModule 4  geometry of shape and size
Module 4 geometry of shape and size
 
Pdm presentation
Pdm presentationPdm presentation
Pdm presentation
 
POTENCIAS Y RAÍCES DE NÚMEROS COMPLEJOS-LAPTOP-3AN2F8N2.pptx
POTENCIAS Y RAÍCES DE NÚMEROS COMPLEJOS-LAPTOP-3AN2F8N2.pptxPOTENCIAS Y RAÍCES DE NÚMEROS COMPLEJOS-LAPTOP-3AN2F8N2.pptx
POTENCIAS Y RAÍCES DE NÚMEROS COMPLEJOS-LAPTOP-3AN2F8N2.pptx
 
Chapter 7.pptx
Chapter 7.pptxChapter 7.pptx
Chapter 7.pptx
 
imc-2018-s.pdf
imc-2018-s.pdfimc-2018-s.pdf
imc-2018-s.pdf
 
Chapter1.integer s.y.b.c.s
Chapter1.integer s.y.b.c.sChapter1.integer s.y.b.c.s
Chapter1.integer s.y.b.c.s
 
Interior-and-Exterior-Angles-of-Polygons.ppt
Interior-and-Exterior-Angles-of-Polygons.pptInterior-and-Exterior-Angles-of-Polygons.ppt
Interior-and-Exterior-Angles-of-Polygons.ppt
 
Question bank -xi (hots)
Question bank -xi (hots)Question bank -xi (hots)
Question bank -xi (hots)
 
Lines and angles
Lines and anglesLines and angles
Lines and angles
 
FS Maths Level 2 - April 8, 2023 (Angles, Circles, 2D shapes area and perimet...
FS Maths Level 2 - April 8, 2023 (Angles, Circles, 2D shapes area and perimet...FS Maths Level 2 - April 8, 2023 (Angles, Circles, 2D shapes area and perimet...
FS Maths Level 2 - April 8, 2023 (Angles, Circles, 2D shapes area and perimet...
 
FS Maths Level 2 – May 13, 2023 (Angles, Circles, 2D shapes (area and perimet...
FS Maths Level 2 – May 13, 2023 (Angles, Circles, 2D shapes (area and perimet...FS Maths Level 2 – May 13, 2023 (Angles, Circles, 2D shapes (area and perimet...
FS Maths Level 2 – May 13, 2023 (Angles, Circles, 2D shapes (area and perimet...
 
FS Maths Level 2 - April 8, 2023 (Angles, Circles, 2D shapes area and perimet...
FS Maths Level 2 - April 8, 2023 (Angles, Circles, 2D shapes area and perimet...FS Maths Level 2 - April 8, 2023 (Angles, Circles, 2D shapes area and perimet...
FS Maths Level 2 - April 8, 2023 (Angles, Circles, 2D shapes area and perimet...
 
Mathematics TAKS Exit Level Review
Mathematics TAKS Exit Level ReviewMathematics TAKS Exit Level Review
Mathematics TAKS Exit Level Review
 
M103-ADEPT 8.pptx
M103-ADEPT 8.pptxM103-ADEPT 8.pptx
M103-ADEPT 8.pptx
 
Ppt Understanding Quadrilaterals (Module 1) Class VIII.pptx
Ppt Understanding Quadrilaterals (Module 1) Class VIII.pptxPpt Understanding Quadrilaterals (Module 1) Class VIII.pptx
Ppt Understanding Quadrilaterals (Module 1) Class VIII.pptx
 
Geometric series
Geometric seriesGeometric series
Geometric series
 

More from antonyge68

Doc1
Doc1Doc1
4 th week
4 th week4 th week
4 th week
antonyge68
 
Third week bmm
Third week bmmThird week bmm
Third week bmm
antonyge68
 
Third week bmm2
Third week bmm2Third week bmm2
Third week bmm2
antonyge68
 
Online assignment communalism
Online assignment communalismOnline assignment communalism
Online assignment communalism
antonyge68
 
Lesson template
Lesson templateLesson template
Lesson template
antonyge68
 
Lesson template ict
Lesson template ictLesson template ict
Lesson template ict
antonyge68
 
Power point
Power pointPower point
Power point
antonyge68
 
Shilakal
ShilakalShilakal
Shilakal
antonyge68
 
Heighest mountains in the world
Heighest mountains in the worldHeighest mountains in the world
Heighest mountains in the world
antonyge68
 
Innovative lesson segment
Innovative lesson segmentInnovative lesson segment
Innovative lesson segment
antonyge68
 
Online assignment
Online assignmentOnline assignment
Online assignment
antonyge68
 
Powerpoint presentaion
Powerpoint presentaionPowerpoint presentaion
Powerpoint presentaion
antonyge68
 
Innovative lesson plan
Innovative lesson planInnovative lesson plan
Innovative lesson plan
antonyge68
 
One’s own work
One’s own workOne’s own work
One’s own work
antonyge68
 
endangered birds in india
endangered birds in indiaendangered birds in india
endangered birds in india
antonyge68
 
endangered animals in india
endangered animals in indiaendangered animals in india
endangered animals in india
antonyge68
 
New new invention- sterilizing spray
New new invention- sterilizing sprayNew new invention- sterilizing spray
New new invention- sterilizing spray
antonyge68
 
Powerpoint presentation jaivavaividyam
Powerpoint presentation jaivavaividyamPowerpoint presentation jaivavaividyam
Powerpoint presentation jaivavaividyam
antonyge68
 

More from antonyge68 (20)

Doc1
Doc1Doc1
Doc1
 
4 th week
4 th week4 th week
4 th week
 
Third week bmm
Third week bmmThird week bmm
Third week bmm
 
Third week bmm2
Third week bmm2Third week bmm2
Third week bmm2
 
Ear
EarEar
Ear
 
Online assignment communalism
Online assignment communalismOnline assignment communalism
Online assignment communalism
 
Lesson template
Lesson templateLesson template
Lesson template
 
Lesson template ict
Lesson template ictLesson template ict
Lesson template ict
 
Power point
Power pointPower point
Power point
 
Shilakal
ShilakalShilakal
Shilakal
 
Heighest mountains in the world
Heighest mountains in the worldHeighest mountains in the world
Heighest mountains in the world
 
Innovative lesson segment
Innovative lesson segmentInnovative lesson segment
Innovative lesson segment
 
Online assignment
Online assignmentOnline assignment
Online assignment
 
Powerpoint presentaion
Powerpoint presentaionPowerpoint presentaion
Powerpoint presentaion
 
Innovative lesson plan
Innovative lesson planInnovative lesson plan
Innovative lesson plan
 
One’s own work
One’s own workOne’s own work
One’s own work
 
endangered birds in india
endangered birds in indiaendangered birds in india
endangered birds in india
 
endangered animals in india
endangered animals in indiaendangered animals in india
endangered animals in india
 
New new invention- sterilizing spray
New new invention- sterilizing sprayNew new invention- sterilizing spray
New new invention- sterilizing spray
 
Powerpoint presentation jaivavaividyam
Powerpoint presentation jaivavaividyamPowerpoint presentation jaivavaividyam
Powerpoint presentation jaivavaividyam
 

Recently uploaded

Guidance_and_Counselling.pdf B.Ed. 4th Semester
Guidance_and_Counselling.pdf B.Ed. 4th SemesterGuidance_and_Counselling.pdf B.Ed. 4th Semester
Guidance_and_Counselling.pdf B.Ed. 4th Semester
Atul Kumar Singh
 
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdf
Welcome to TechSoup   New Member Orientation and Q&A (May 2024).pdfWelcome to TechSoup   New Member Orientation and Q&A (May 2024).pdf
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdf
TechSoup
 
How libraries can support authors with open access requirements for UKRI fund...
How libraries can support authors with open access requirements for UKRI fund...How libraries can support authors with open access requirements for UKRI fund...
How libraries can support authors with open access requirements for UKRI fund...
Jisc
 
Honest Reviews of Tim Han LMA Course Program.pptx
Honest Reviews of Tim Han LMA Course Program.pptxHonest Reviews of Tim Han LMA Course Program.pptx
Honest Reviews of Tim Han LMA Course Program.pptx
timhan337
 
The Accursed House by Émile Gaboriau.pptx
The Accursed House by Émile Gaboriau.pptxThe Accursed House by Émile Gaboriau.pptx
The Accursed House by Émile Gaboriau.pptx
DhatriParmar
 
Additional Benefits for Employee Website.pdf
Additional Benefits for Employee Website.pdfAdditional Benefits for Employee Website.pdf
Additional Benefits for Employee Website.pdf
joachimlavalley1
 
Operation Blue Star - Saka Neela Tara
Operation Blue Star   -  Saka Neela TaraOperation Blue Star   -  Saka Neela Tara
Operation Blue Star - Saka Neela Tara
Balvir Singh
 
Home assignment II on Spectroscopy 2024 Answers.pdf
Home assignment II on Spectroscopy 2024 Answers.pdfHome assignment II on Spectroscopy 2024 Answers.pdf
Home assignment II on Spectroscopy 2024 Answers.pdf
Tamralipta Mahavidyalaya
 
Phrasal Verbs.XXXXXXXXXXXXXXXXXXXXXXXXXX
Phrasal Verbs.XXXXXXXXXXXXXXXXXXXXXXXXXXPhrasal Verbs.XXXXXXXXXXXXXXXXXXXXXXXXXX
Phrasal Verbs.XXXXXXXXXXXXXXXXXXXXXXXXXX
MIRIAMSALINAS13
 
The approach at University of Liverpool.pptx
The approach at University of Liverpool.pptxThe approach at University of Liverpool.pptx
The approach at University of Liverpool.pptx
Jisc
 
TESDA TM1 REVIEWER FOR NATIONAL ASSESSMENT WRITTEN AND ORAL QUESTIONS WITH A...
TESDA TM1 REVIEWER  FOR NATIONAL ASSESSMENT WRITTEN AND ORAL QUESTIONS WITH A...TESDA TM1 REVIEWER  FOR NATIONAL ASSESSMENT WRITTEN AND ORAL QUESTIONS WITH A...
TESDA TM1 REVIEWER FOR NATIONAL ASSESSMENT WRITTEN AND ORAL QUESTIONS WITH A...
EugeneSaldivar
 
Adversarial Attention Modeling for Multi-dimensional Emotion Regression.pdf
Adversarial Attention Modeling for Multi-dimensional Emotion Regression.pdfAdversarial Attention Modeling for Multi-dimensional Emotion Regression.pdf
Adversarial Attention Modeling for Multi-dimensional Emotion Regression.pdf
Po-Chuan Chen
 
A Strategic Approach: GenAI in Education
A Strategic Approach: GenAI in EducationA Strategic Approach: GenAI in Education
A Strategic Approach: GenAI in Education
Peter Windle
 
Instructions for Submissions thorugh G- Classroom.pptx
Instructions for Submissions thorugh G- Classroom.pptxInstructions for Submissions thorugh G- Classroom.pptx
Instructions for Submissions thorugh G- Classroom.pptx
Jheel Barad
 
Thesis Statement for students diagnonsed withADHD.ppt
Thesis Statement for students diagnonsed withADHD.pptThesis Statement for students diagnonsed withADHD.ppt
Thesis Statement for students diagnonsed withADHD.ppt
EverAndrsGuerraGuerr
 
The Roman Empire A Historical Colossus.pdf
The Roman Empire A Historical Colossus.pdfThe Roman Empire A Historical Colossus.pdf
The Roman Empire A Historical Colossus.pdf
kaushalkr1407
 
Polish students' mobility in the Czech Republic
Polish students' mobility in the Czech RepublicPolish students' mobility in the Czech Republic
Polish students' mobility in the Czech Republic
Anna Sz.
 
The basics of sentences session 5pptx.pptx
The basics of sentences session 5pptx.pptxThe basics of sentences session 5pptx.pptx
The basics of sentences session 5pptx.pptx
heathfieldcps1
 
Synthetic Fiber Construction in lab .pptx
Synthetic Fiber Construction in lab .pptxSynthetic Fiber Construction in lab .pptx
Synthetic Fiber Construction in lab .pptx
Pavel ( NSTU)
 
BÀI TẬP BỔ TRỢ TIẾNG ANH GLOBAL SUCCESS LỚP 3 - CẢ NĂM (CÓ FILE NGHE VÀ ĐÁP Á...
BÀI TẬP BỔ TRỢ TIẾNG ANH GLOBAL SUCCESS LỚP 3 - CẢ NĂM (CÓ FILE NGHE VÀ ĐÁP Á...BÀI TẬP BỔ TRỢ TIẾNG ANH GLOBAL SUCCESS LỚP 3 - CẢ NĂM (CÓ FILE NGHE VÀ ĐÁP Á...
BÀI TẬP BỔ TRỢ TIẾNG ANH GLOBAL SUCCESS LỚP 3 - CẢ NĂM (CÓ FILE NGHE VÀ ĐÁP Á...
Nguyen Thanh Tu Collection
 

Recently uploaded (20)

Guidance_and_Counselling.pdf B.Ed. 4th Semester
Guidance_and_Counselling.pdf B.Ed. 4th SemesterGuidance_and_Counselling.pdf B.Ed. 4th Semester
Guidance_and_Counselling.pdf B.Ed. 4th Semester
 
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdf
Welcome to TechSoup   New Member Orientation and Q&A (May 2024).pdfWelcome to TechSoup   New Member Orientation and Q&A (May 2024).pdf
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdf
 
How libraries can support authors with open access requirements for UKRI fund...
How libraries can support authors with open access requirements for UKRI fund...How libraries can support authors with open access requirements for UKRI fund...
How libraries can support authors with open access requirements for UKRI fund...
 
Honest Reviews of Tim Han LMA Course Program.pptx
Honest Reviews of Tim Han LMA Course Program.pptxHonest Reviews of Tim Han LMA Course Program.pptx
Honest Reviews of Tim Han LMA Course Program.pptx
 
The Accursed House by Émile Gaboriau.pptx
The Accursed House by Émile Gaboriau.pptxThe Accursed House by Émile Gaboriau.pptx
The Accursed House by Émile Gaboriau.pptx
 
Additional Benefits for Employee Website.pdf
Additional Benefits for Employee Website.pdfAdditional Benefits for Employee Website.pdf
Additional Benefits for Employee Website.pdf
 
Operation Blue Star - Saka Neela Tara
Operation Blue Star   -  Saka Neela TaraOperation Blue Star   -  Saka Neela Tara
Operation Blue Star - Saka Neela Tara
 
Home assignment II on Spectroscopy 2024 Answers.pdf
Home assignment II on Spectroscopy 2024 Answers.pdfHome assignment II on Spectroscopy 2024 Answers.pdf
Home assignment II on Spectroscopy 2024 Answers.pdf
 
Phrasal Verbs.XXXXXXXXXXXXXXXXXXXXXXXXXX
Phrasal Verbs.XXXXXXXXXXXXXXXXXXXXXXXXXXPhrasal Verbs.XXXXXXXXXXXXXXXXXXXXXXXXXX
Phrasal Verbs.XXXXXXXXXXXXXXXXXXXXXXXXXX
 
The approach at University of Liverpool.pptx
The approach at University of Liverpool.pptxThe approach at University of Liverpool.pptx
The approach at University of Liverpool.pptx
 
TESDA TM1 REVIEWER FOR NATIONAL ASSESSMENT WRITTEN AND ORAL QUESTIONS WITH A...
TESDA TM1 REVIEWER  FOR NATIONAL ASSESSMENT WRITTEN AND ORAL QUESTIONS WITH A...TESDA TM1 REVIEWER  FOR NATIONAL ASSESSMENT WRITTEN AND ORAL QUESTIONS WITH A...
TESDA TM1 REVIEWER FOR NATIONAL ASSESSMENT WRITTEN AND ORAL QUESTIONS WITH A...
 
Adversarial Attention Modeling for Multi-dimensional Emotion Regression.pdf
Adversarial Attention Modeling for Multi-dimensional Emotion Regression.pdfAdversarial Attention Modeling for Multi-dimensional Emotion Regression.pdf
Adversarial Attention Modeling for Multi-dimensional Emotion Regression.pdf
 
A Strategic Approach: GenAI in Education
A Strategic Approach: GenAI in EducationA Strategic Approach: GenAI in Education
A Strategic Approach: GenAI in Education
 
Instructions for Submissions thorugh G- Classroom.pptx
Instructions for Submissions thorugh G- Classroom.pptxInstructions for Submissions thorugh G- Classroom.pptx
Instructions for Submissions thorugh G- Classroom.pptx
 
Thesis Statement for students diagnonsed withADHD.ppt
Thesis Statement for students diagnonsed withADHD.pptThesis Statement for students diagnonsed withADHD.ppt
Thesis Statement for students diagnonsed withADHD.ppt
 
The Roman Empire A Historical Colossus.pdf
The Roman Empire A Historical Colossus.pdfThe Roman Empire A Historical Colossus.pdf
The Roman Empire A Historical Colossus.pdf
 
Polish students' mobility in the Czech Republic
Polish students' mobility in the Czech RepublicPolish students' mobility in the Czech Republic
Polish students' mobility in the Czech Republic
 
The basics of sentences session 5pptx.pptx
The basics of sentences session 5pptx.pptxThe basics of sentences session 5pptx.pptx
The basics of sentences session 5pptx.pptx
 
Synthetic Fiber Construction in lab .pptx
Synthetic Fiber Construction in lab .pptxSynthetic Fiber Construction in lab .pptx
Synthetic Fiber Construction in lab .pptx
 
BÀI TẬP BỔ TRỢ TIẾNG ANH GLOBAL SUCCESS LỚP 3 - CẢ NĂM (CÓ FILE NGHE VÀ ĐÁP Á...
BÀI TẬP BỔ TRỢ TIẾNG ANH GLOBAL SUCCESS LỚP 3 - CẢ NĂM (CÓ FILE NGHE VÀ ĐÁP Á...BÀI TẬP BỔ TRỢ TIẾNG ANH GLOBAL SUCCESS LỚP 3 - CẢ NĂM (CÓ FILE NGHE VÀ ĐÁP Á...
BÀI TẬP BỔ TRỢ TIẾNG ANH GLOBAL SUCCESS LỚP 3 - CẢ NĂM (CÓ FILE NGHE VÀ ĐÁP Á...
 

Digital text book

  • 1. MATHE MATICS Std. VIII A TEXT BOOK OF MATHEMATICS STD : VIII
  • 2. MATHEMATICS DIGITAL TEXT BOOK Std. VIII Anchulekshmi A R B.Ed Mathematics Reg.No. 18014350002
  • 3. CONTENTS Chapter I Equations 1. Addition and Subtraction 2. Multiplication and Division 3. Method ofAlgebra 4. Different Problems 1. Polygons Chapter II Polygons 2. Sum of the angles 3. External angles 4. Unchanging sum 5. Regular Polygons
  • 4. Chapter 1 EQUATIONS Equations are algebraic sentences denoting equality of numbers Addition and Subtraction i. Addition of numbers Eg: 40 + 3 = 43 50 + 3 = 53 H. Subtraction of Numbers Eg: 40 - 3 = 37 50 - 3 = 47 Problems related to Addition and Subtraction of Numbers Eg: Rajan said "if 6 more marks were granted. My marks in Maths would be 100." Howmany marks did he get? Ans : It will become 100 if 6 more added. So his marks is 6 less than 100. 100 - 6 = 94. This is Rajans Marks. Equations 1
  • 5. Multiplication and Division i. Multiplication of Numbers Eg: 40 x 3 = 120 22 x 3 = 66 ii. Division of Numbers Eg: 125 + 5 = 25 42+2=21 Problems related to Multiplication and Division of Numbers Eg: A number multiplied by 12 gIves 756. Which number was multiplied? Ans: 756 + 12 = 63 Method of Algebra It is easy to solve all the problems of numbers using algebra. The unknown number or variable ofthe equation is x. Then to find x, in all cases we used the method of inverse operation in charge subtraction to addition, change Equations 2
  • 6. ... multiplication to division and change division to ~. tnlltiplication. The formulas are if x+a= b, x =b - a if x-a = b, x=b+a b if ax=b X= -, a if ~=b , x=bxa a if ax+b = c, ax = c-b c-b x=-- a To Recollect x + x = 2x x + 2x = 3x 2x + 3x = 5x 5x - x = 4x 2x - x = x 7x - 5x = 2x 2x + 1 = 2x + 1 it self Equations 3
  • 7. Different Problems Eg: When 10 was added to 2 times a number, we get 4 times the number. What is the number? Ans: Let the number be x 2x+10 = 4x There is variable on both sides ofthe equal to. sign in this equation. Subtract 2x from both sides of the equal to sign Equations 2x + 10 - 2x = 4x - 2x 10 = 2x 2x = 10 10 x=-=5 2 4
  • 8. Chapter 2 POLYGONS Polygons is the common name given to shapes with three or more sides. Eg:6D Sum of the Angles The sum ofthe angles of a polygon of n sides is (n-2) x 1800 The sum of the angles of a polygon is always a multiple of 180. Eg: What is the sum ofthe angles ofa polygon of52 sides. Ans : Sum ofthe angles = (n-2) x 1800 = (52 - 2) x 1800 =50x180 = 90000 External Angles If one side of a triangle is extended. We get an exter- nal.angle. Polygons 5
  • 9. Co In triangle ABC, side BC is extended to D. LACD is an external angle at corner C LACB is the internal angle at corner C. Since these two angles form a linear pair. LACD + LACB = 1800 or LACD = 1800 - LACB Unchanging Sum D In i1ABC, the sum of the internal angle and external angle at corner A = 1800 (linear pair). In i1ABC, the sum of the internal angle and external Polygons 6
  • 10. angle at comer B = 1800 (Linear pair) In L1ABC, the sum of the internal angle and external angle at comer C = 1800 (linear pair) Sum of the three internal angles and three external angles of L1ABC = 180x3 = 5400 But sum ofthe internal angles = 1800 So sum of the angles external = 540 - 180 = 3600 In any triangle, the sum ofthe external angles is 360°. Now let us examine the case in a quadrilateral. Sum of the internal angle and external angle at A = 1800 Sum of the internal angle and external angle at all four corners = 180 x 4 = 7200 A ------L....LJ B Polygons 7
  • 11. But sum of the internal angles of a quadrilateral is 360°. So sum ofthe external angles of a quadrilateral = 720 - 360 = 360° In the same way examine the sum ofthe external angles of a pentagon, hexagone, etc. Always we get it as 360°. Sum ofthe external angles ofany polygon is 360°. Eg: The angles of 18 sided polygon are equal. What is the measure of each external angle? Ans: Sum ofthe external angles ofthe polygon with 18 sides = 360°. Since the angles are equal, external angles are also equal. Measure of each external angle = 360 = 200 18 Regular Polygons Polygons with all sides equal and all angles equal are called regular polygons. Polygons 8
  • 12. MATHE MATICS Std. VIII A TEXT BOOK OF MATHEMATICS STD : VIII