Topics
Integers
- Natural Numbers
- Whole Numbers
- Negative and Positive Numbers
- Integers
- Representation of Integers on the Number Line
- Ordering of Integers
- Addition of Integers
- Subtraction of Integers
- Properties of Addition and Subtraction of Integers
- Multiplication of a Positive and a Negative Integers
- Multiplication of Two Negative Integers
- Product of Three Or More Negative Integers
- Closure Property of Multiplication of Integers
- Commutative Property of Multiplication of Integers
- Multiplication of Integers with Zero
- Multiplicative Identity of Integers
- Associative Property of Multiplication of Integers
- Distributive Property of Multiplication of Integers
- Making Multiplication Easier of Integers
- Division of Integers
- Properties of Division of Integers
Fractions and Decimals
- Concept of Fraction
- Types of Fractions
- Concept of Proper and Improper Fractions
- Concept of Mixed Fractions
- Concept of Equivalent Fractions
- Like and Unlike Fraction
- Comparing Fractions
- Addition of Fraction
- Subtraction of Fraction
- Multiplication of a Fraction by a Whole Number
- Using Operator 'Of' with Multiplication and Division
- Multiplication of Fraction
- Division of Fractions
- Concept of Reciprocals or Multiplicative Inverses
- Problems Based on Fraction
- The Decimal Number System
- Comparing Decimal Numbers
- Addition of Decimal Fraction
- Subtraction of Decimal Numbers
- Multiplication of Decimal Numbers
- Division of Decimal Numbers
- Problems Based on Decimal Numbers
Data Handling
Simple Equations
Lines and Angles
The Triangle and Its Properties
- Basic Concepts of Triangles
- Classification of Triangles based on Sides
- Classification of Triangles based on Angles
- Median of a Triangle
- Altitudes of a Triangle
- Exterior Angle of a Triangle and Its Property
- Some Special Types of Triangles - Equilateral and Isosceles Triangles
- Basic Properties of a Triangle
- Right-angled Triangles and Pythagoras Property
Congruence of Triangles
- Similarity and Congruency of Figures
- Congruence Among Line Segments
- Congruence of Angles
- Congruence of Triangles
- Criteria for Congruence of Triangles
- Criteria for Similarity of Triangles
- SAS Congruence Criterion
- ASA Congruence Criterion
- RHS Congruence Criterion
- Exceptional Criteria for Congruence of Triangles
Comparing Quantities
- Ratio
- Concept of Equivalent Ratios
- Proportion
- Unitary Method
- Basic Concept of Percentage
- Estimation in Percentages
- Interpreting Percentages
- Conversion between Percentage and Fraction or Decimal
- Ratios to Percents
- Increase Or Decrease as Percent
- Basic Concepts of Profit and Loss
- Profit or Loss as a Percentage
- Calculation of Interest
Rational Numbers
- Rational Numbers
- Equivalent Rational Number
- Positive and Negative Rational Numbers
- Rational Numbers on a Number Line
- Rational Numbers in Standard Form
- Comparison of Rational Numbers
- Rational Numbers Between Two Rational Numbers
- Addition of Rational Number
- Subtraction of Rational Number
- Multiplication of Rational Numbers
- Division of Rational Numbers
Perimeter and Area
- Basic Concepts in Mensuration
- Concept of Perimeter
- Perimeter of a Rectangle
- Perimeter of Squares
- Perimeter of Triangle
- Perimeter of Polygon
- Concept of Area
- Area of Square
- Area of Rectangle
- Triangles as Parts of Rectangles and Square
- Generalising for Other Congruent Parts of Rectangles
- Area of a Parallelogram
- Area of a Triangle
- Circumference of a Circle
- Area of Circle
- Conversion of Units
- Problems based on Perimeter
- Problems based on Area
Practical Geometry
- Construction of a Line Parallel to a Given Line, Through a Point Not on the Line
- Construction of Triangles
- Constructing a Triangle When the Length of Its Three Sides Are Known (SSS Criterion)
- Constructing a Triangle When the Lengths of Two Sides and the Measure of the Angle Between Them Are Known. (SAS Criterion)
- Constructing a Triangle When the Measures of Two of Its Angles and the Length of the Side Included Between Them is Given. (ASA Criterion)
- Constructing a Right-angled Triangle When the Length of One Leg and Its Hypotenuse Are Given (RHS Criterion)
Algebraic Expressions
Exponents and Powers
- Concept of Exponents
- Multiplying Powers with the Same Base
- Dividing Powers with the Same Base
- Taking Power of a Power
- Multiplying Powers with Different Base and Same Exponents
- Dividing Powers with Different Base and Same Exponents
- Numbers with Exponent Zero, One, Negative Exponents
- Miscellaneous Examples Using the Laws of Exponents
- Decimal Number System Using Exponents and Powers
- Crores
Symmetry
Visualizing Solid Shapes
- Introduction
- Symbol of Percentage
- Formula: Percentage
- Steps to Convert Fractions to Percentages
- Example 1
- Example 2
- Real-Life Examples
- Key Points Summary
Introduction
What is a Percentage?
- The word "percent" means "out of 100".
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It tells us how many parts out of 100 something represents.
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For example, 25% means 25 parts out of 100 parts.
- When a fraction is written in such a way that the denominator is 100, then the numerator of that fraction is called a 'percent' or 'percentage'.
Symbol of Percentage
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The symbol for percent is %.
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So, 75% means 75 out of 100.
Formula: Percentage
Percentage = `"value"/"Total value"` × 100
% (Percentage) = `"Part"/"Whole"` × 100
Percent is the numerator of a fraction with a denominator of 100.
Steps to Convert Fractions to Percentages
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Step 1: Change the fraction to an equivalent fraction with denominator 100.
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Step 2: The numerator becomes the percentage.
Example:
`7/50` = `"7 × 2 "/"50 × 2"`= `14/100` = 14%
Example 1
1.60 out of 100
= `"60"/"100"`
= 60 as a percent, written as 60%.
2. `"3"/"5"` × 100%
= 60 %
Example 2
Express each of the following statements in the percentage form:
- 5 out of 20 eggs are bad.
- 3 children in a class of 30 are absent.
Solution:
(i) 5 out of 20 eggs are bad, which means `"5"/"20"`
And `"5"/"20"` = `"5 × 5 "/"20 × 5"`= `"25"/"100"` = 25%
∴ 25% eggs are bad.
(ii) 3 children out of 30 are absent is written as `"3"/"30"`
And `"3"/"30"` = `"1"/"10"`= `"10"/"100"` = 10%
∴ 10% children are absent.
Real-Life Examples
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If an exam is of 100 marks and Geeta scores 83, she scored 83% marks.
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If Rohit scored 67%, it means he got 67 marks out of 100.
Key Points Summary
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"Percent" means "out of 100".
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The symbol % represents percentage.
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Convert fractions to percentages by making the denominator 100 and the numerator the percentage.
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Visualising percentages with grids and tables helps in understanding.
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Percentages are useful to compare parts of a whole easily.
Test Yourself
Shaalaa.com | What is Percentage?
Related QuestionsVIEW ALL [312]
Air is an important inexhaustible natural resource. It is essential for the survival of human beings, microbes, plants, and animals. The following table shows the percentage of various gases in the air.
| Contents of air | Percentage (by volume) |
| Nitrogen | 78 |
| Oxygen | 21 |
| Other (carbon dioxide, inert gases, water vapours, etc.) | 1 |
In 800 m3 of air, calculate the approximate quantities of nitrogen, oxygen, and other gases.
