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8th Class

Notes - Synthetic Fibres Plastics

  Synthetic Fibres and Plastics   ·                     Fibres that are obtained by chemical processing of petrochemicals are called synthetic fibres. Like natural fibres, these fibres can also be woven into fabrics. ·                     Synthetic fibres and plastics are made of very large units called polymers. ·                     Polymers are made up of many smaller units called monomers. ·                     Synthetic fibres have various uses in our day to day life. They are used in household articles like ropes, buckets, furniture, containers, etc. Apart from items of household uses, they are also used in aircrafts, ships, spacecraft?s, healthcare, etc. ·                     Rayon, nylon, polyester and acrylic are some of the main types of synthetic fibres. ·                     The properties of rayon are similar more...
Catgeory: 8th Class

Notes - Crop Production Management

  Crop Production and Management   ·                     Crop production and management plays a key role in our country's economy. By adopting advanced and latest technologies in agriculture, enough yields of crops can be grown to provide food to our growing population. ·                     The plants of same kind grown and cultivated at one place on a large scale are called a crop. ·                     There are mainly two types of crops grown in India - rabi and kharif crops. ·                     Rabi crops are the agricultural crops that are sown in winter and harvested in the spring. Wheat, Gram, Pea, Mustard, Linseed, Barley, Peas are the examples of rabi crop. ·                     Kharif crops are referred to those crops that are sown in the rainy more...
Catgeory: 8th Class

Number System

  Number System   Learning Objectives
  • Properties of Rational Numbers
  • Square and Square Roots
  • Cube and Cube Roots
  • Playing with Numbers
  • Divisibility Test
  Properties of Rational Numbers Rational numbers are the numbers that can be expressed in the form \[\frac{p}{q}\], where p and q are integers and \[q\ne ~0\] . The collection of rational numbers is denoted by Q. These rational numbers satisfy following laws or properties
  •  Rational numbers are closed under addition, subtraction and multiplication. If a, b are any two rational numbers, then the sum, difference and product of these rational numbers is also a rational number, thus we can say that rational numbers satisfy the closure law.
  • Rational numbers are commutative under addition and multiplication. If a, b are rational numbers, then:
  • Commutative law under addition: \[\mathbf{a}+\mathbf{b}=\mathbf{b}+\mathbf{a}\]
  • Commutative law under multiplication: \[\mathbf{a}\times \mathbf{b}=\mathbf{b}\times \mathbf{a}\]
 
Catgeory: 8th Class

Geometry

  Geometry   Learning Objectives  
  • Understanding Polygons
  • Parallelogram
  • Rhombus
  • Trapezium
  • Kite
  • Rectangle
  • Square
  • Practical Geometry
  Understanding Polygons  
  • A polygon is a simple closed curve made up of only line segments.
  • A line segment that connects the two non-consecutive vertices of a polygon is called a diagonal.
  • A convex polygon is defined as a polygon with all its interior angles less than \[180{}^\circ \]. This means that all the vertices of the polygon will point outwards, away from the interior of the shape.
 
  • A concave polygon is defined as a polygon with one or more interior angles greater than \[180{}^\circ \]. It looks like a vertex has been 'pushed in' towards the inside of the polygon.
 
Catgeory: 8th Class

Notes - Mensuration

  Mensuration   Learning Objectives  
  • Mensuration
  • Visualizing Solid Shapes
  Mensuration   Mensuration is the branch of mathematics which deal with the study of geometric shapes, their area, volume and related parameters. Some important formulae of area and volume are listed below.   Area of some plane figures:  
Figure Shape Area
more...
Catgeory: 8th Class

Notes - Algebra

  Algebra             Learning Objectives  
  • Liner equation in one variable
  • Algebraic expression and identities
  • Factorisation 
  • Exponents and Powers
  • Direct and Indirect Proportion
  • Comparing Quantities
  Linear Equations in one Variable  
  • An algebraic equation is an equality involving variables and an equality sign. The expression on the left of the equality sign is the Left Hand Side (LHS). The expression on the right of the equality sign is the Right Hand Side (RHS).
  • An algebraic equation involving only one variable with its highest power 1 is called a linear equation.
  • The values of the expressions on the LHS and RHS are equal. This happens to be true only for certain values of the variable. These values are the solutions of the equation.
  Example 1. Solve the equation: \[\frac{\mathbf{0}\mathbf{.5}\left( \mathbf{z-0}\mathbf{.4} \right)}{\mathbf{3}\mathbf{.5}}\mathbf{-}\frac{\mathbf{0}\mathbf{.6}\left( more...
Catgeory: 8th Class

Notes - Statistics

  Statistics   Learning Objectives  
  • Data Handing
  • Introduction to Graphs
  Data Handling  
  • Pictograph: A pictograph is a way of showing data using images.
  • The number of times that a particular entry occurs in a data is called its frequency.
  • In the class interval, 10-20, 10 is called the lower class limit and 20 is called the upper class limit.
  • The difference between the upper class limit and lower class limit is called the width or size of the class interval.
  Introduction to Graphs  
  • Bar Graph: It is a display of information using bars of uniform width, their heights being proportional to the respective values.
  • Double Bar Graph: It is a type of bar graph showing two sets of data simultaneously. It is useful for the comparison of the data.
  • Histogram: A histogram more...
Catgeory: 8th Class

Analogy

  Analogy   Learning Objectives
  • What is Analogy
  • Worker and Product
  • Worker and Tool Relationship
  • Tool and Action
  • Worker and Working Place
  • Product and Raw Material
  • Quantity and Unit
  • Study and Topic
  • Animal and Young Ones
  Analogy   In general, meaning of analogy is similarity. But, in terms of reasoning, the meaning of analogy is logical similarity in two or more things. This similarity may be on the basis of properties, kinds, traits, shapes etc. In the questions based on analogy, a particular relationship is given and another similar relationship has to be identified from the alternatives provided. Analogy tools are therefore meant to test one's ability to reason - how far you are able to compare and comprehend the relationship that exists between two objects, things or figures. There are many possibilities in establishing a relationship. Here are some useful more...
Catgeory: 8th Class

Blood Relations

  Blood Relation             Learning Objectives
  • Introduction
  • Understanding of some relations
  • Relations from one generation to next
  • Types of questions
  Introduction Blood relation means a biological relation. Remember a wife and husband are not biologically related but they are biological parents of their own children. Similarly, brother, sister, paternal grandfather, paternal grandmother, maternal grandfather, maternal grandmother, grandson, grandmother, niece, cousin etc. are our blood relatives.   Let's understand some relations:
  • Mother's or father's son = Brother
  • Mother's or father's daughter = Sister
  • Mother's or father's brother = Uncle
  • Mother's or father's sister = Aunt
  • Mother's or father's father = Grandfather
  • Mother's or father's mother = Grandmother
  • Son's wife = Daughter-in-Law
  • Daughter's husband = Son-in-Law
  • Husband's or wife's sister = Sister-in-Law
  • Husband's or wife's brother = Brother-in-Law
  • Brother's son = Nephew
  • Brother's daughter = Niece
  • Uncle or more...
Catgeory: 8th Class

Series

  Series   Learning Objectives
  • Number Series
  • Letter Series
  • Mixed Series
  Series Series is a sequence of elements put together according to a certain rule. Series is mainly of three types - Letter Series, Number Series and Mixed Series.     Number Series Such type of series consists of numbers that are arranged in a particular sequence, in the question related to number series, candidates are asked either to insert a missing number or find the one that does not follow the pattern of the series. On this basis we divided the questions of number series in two types. Let’s discuss them one by one.   Type - I (To insert a missing number)
  • Example 1
4, 9, 19, 34, 54, ?, 109 (a) 89                            (b) 84 (c) 74                                        (d) 79 (e) more...
Catgeory: 8th Class

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