A Story of Numbers Class 8 Mathematics Free Notes and Mind Map (Free PDF Download)

numbers

Numbers are so much part of our daily life that we rarely think about where they came from. But the story of numbers is actually a long journey that spans thousands of years and many civilizations. Let’s study how humans developed the number system we use today.

Reema’s Curiosity

When Reema was looking through an old book, she found strange symbols that ancient Mesopotamians used for numbers. This made her curious – why don’t we use those symbols today? Where did our modern numbers come from?

Humans have needed to count things since the Stone Age. They needed to keep track of:

  • Food supplies
  • Number of animals in their herds
  • Items for trade
  • Important dates and rituals
  • Days passing by
  • Seasonal events like new moon appearances

Early counting systems looked very different from the numbers we use today. The journey from those ancient symbols to our modern digits is a long and interesting one.

Origin of Modern Number System

The structure of our modern number system actually originated thousands of years ago in India. This is an imp fact that many people don’t know.

Ancient Indian Contributions

  • Ancient Indian texts like Yajurveda Samhita mentioned number names based on powers of 10
  • Numbers were listed from one (eka) to ten thousand (āyuta) and went up to 10¹² and even beyond
  • The modern digit system using 0 through 9 also developed in India around 2000 years ago
  • This happened much earlier than most people realize

Historical Development Timeline

Early Manuscripts

  • The first known instance of ten digits including zero appeared in the Bakhshali manuscript from 3rd century CE
  • Zero was written as a dot in these early manuscripts
  • This was revolutionary because earlier systems didn’t have a symbol for “nothing”

Aryabhata’s Contribution

  • In 499 CE, Aryabhata became the first mathematician to fully explain the Indian system of 10 symbols
  • He performed elaborate scientific computations using these Indian numerals
  • His work showed how powerful and practical this system was

Transmission to the World

The Indian number system didn’t stay in India. It gradually spread to other parts of the world.

Arab World (800 CE)

  • Indian number system was transmitted to the Arab world by 800 CE
  • Al-Khwārizmī popularized it through his book “On Calculation with Hindu Numerals” in 825 CE
  • Al-Kindi also wrote “On Use of Hindu Numerals” in 830 CE
  • Arab scholars correctly called them “Hindu numerals” because they knew the origin

European Adoption

  • From Arab world, Hindu numerals reached Europe and Africa by 1100 CE
  • Fibonacci around 1200 CE strongly advocated adoption of Indian numerals in Europe
  • However, Roman numerals were deeply ingrained in European thinking
  • Indian numerals gained widespread use only during Renaissance by 17th century
  • Not adopting them earlier would have seriously impeded scientific progress

The Naming Confusion

There’s an interesting story about what these numbers are called:

  • Europeans called them “Arabic numerals” because they learned about them from Arabs
  • This reflected their European perspective and limited knowledge of history
  • Arab scholars correctly called them “Hindu numerals” because they knew the true source
  • During colonization period, the European term “Arabic numerals” became widely used globally
  • Recently this historical mistake is being corrected in textbooks worldwide
  • Most common terms now are Hindu numerals, Indian numerals, or Hindu-Arabic numerals

Important Note: The word “Hindu” here refers to geography and people of ancient India, not religion. It’s a geographical and cultural term.

Evolution of Digit Shapes

The shapes of our digits evolved over many centuries:

StageDescription
Brahmi ScriptOriginal ancient Indian script
Hindu (Gwalior)Early medieval Indian form
Sanskrit-DevanagariClassical Indian form
West ArabicForm used in western Arab world
East ArabicForm used in eastern Arab world
11th Century ApicesEuropean medieval form
15th-16th CenturyRenaissance European form
ModernCurrent digits 1, 2, 3, 4, 5, 6, 7, 8, 9, 0

The shapes we use today are the result of this long evolution across different cultures and writing systems.

The Mechanism of Counting

Before we had our modern number system, how did people count things? Let’s study the problems they faced and the solutions they developed.

Stone Age Counting Problems

Imagine you’re a shepherd in the Stone Age. You face these problems:

  • How to ensure all cows returned safely after grazing
  • How to compare herd size with your neighbor
  • How to determine how many more cows needed to have equal numbers
  • How to keep track without writing

These simple questions led humans to develop counting methods.

Method 1: Using Physical Objects

The simplest method was using physical objects as counters.

How It Worked

  • Used pebbles, sticks, or any abundant objects
  • One stick represented one cow in the herd
  • The collection of sticks tells you the number of cows
  • This creates one-to-one mapping between cows and sticks
  • Each cow is mapped to exactly one stick

This method works but has limitations – imagine carrying thousands of sticks to count a large herd!

Method 2: Using Sounds or Names

Another method was using standard sequence of sounds.

Sound-Based Counting

  • Use alphabet letters or specific sounds in fixed order
  • Create one-to-one mapping between objects and letters
  • Follow the order carefully
  • This gives verbal representation of numbers

Limitation: English alphabet is limited to 26 objects only. What do you do after that?

Method 3: Using Written Symbols

Written symbols arranged in sequence can also work for counting.

Examples

  • Roman numeral system: I, II, III, IV, V, VI, VII, VIII, IX, X
  • Extensions possible for larger numbers
  • But requires creating more and more symbols

This standard sequence is what we call a number system.

Requirements for Number Systems

For any counting system to work well, it needs:

  • Fixed order of objects, names, or written symbols
  • One-to-one mapping between collection being counted and standard sequence
  • The sequence should be unending (infinite)
  • It should be easy to use and remember

The Challenge: Creating an unending standard sequence that remains practical:

  • Sticks give unending sequence but impractical for large collections
  • Letter sounds are convenient but limited in range
  • We need something better!

Some Early Number Systems

Different civilizations developed different solutions to the counting problem. Let’s study some of them.

I. Use of Body Parts

Many groups of people used hands and body parts for counting.

How It Worked

  • Papua New Guinea tribes still use body parts as standard sequence
  • Systematic counting using fingers, toes, and other body parts
  • Natural progression from familiar body landmarks
  • Easy to remember because you carry it with you always

This method works well for small numbers but becomes complicated for large numbers.

II. Tally Marks on Bones and Surfaces

This is the oldest method of number representation we have evidence for.

Tally System

  • Make notches on bones or marks on cave walls
  • One mark made for each object being counted
  • Final collection of marks represents total number
  • Similar to using sticks but marks are permanent

Archaeological Evidence
Two imp artifacts show this method:

ArtifactAgeLocationDescription
Lebombo Bone44,000 yearsSouth AfricaHas 29 notches, possibly lunar calendar
Ishango Bone20,000-35,000 yearsCongoNotches in columns, possibly calendrical systems

These are considered the oldest mathematical artifacts ever found!

III. Number Names from Counting in Twos

Some tribes developed interesting number naming systems.

Gumulgal Tribe (Australia)

  • Basic words: urapon (1), ukasar (2)
  • Number 3: ukasar-urapon (2+1)
  • Number 4: ukasar-ukasar (2+2)
  • Number 5: 2+2+1
  • Number 6: 2+2+2
  • Numbers greater than 6 were just called ras

Global Similarities
Three geographically distant groups developed very similar systems:

  • Bakairi (South America): tokale (1), ahage (2), ahage tokale (3)
  • Bushmen (South Africa): xa (1), t’oa (2), quo (3)
  • Gumulgal (Australia): As described above

This suggests either common ancestors or convergent evolution – similar problems led to similar solutions.

IV. Roman Numerals

Roman numerals are more sophisticated than tally systems.

Landmark Numbers
The Romans used special symbols for certain numbers:

  • I = 1
  • V = 5
  • X = 10
  • L = 50
  • C = 100
  • D = 500
  • M = 1000

How Numbers Were Represented
Numbers were represented by grouping into landmark numbers. For example:

  • 2367 = MMCCCLXVII
  • This breaks down as: 1000+1000+100+100+100+50+10+5+1+1

Advantages and Disadvantages

  • More efficient than pure tally systems
  • Addition is possible by grouping symbols together
  • Multiplication is very difficult without converting to Hindu numerals
  • Abacus was used as calculating tool for complex operations
  • Only specially trained people could perform calculations

This limitation is why Roman numerals were eventually replaced.

Advantages of Grouping Systems

Why did people start grouping numbers instead of just counting one by one?

Human Perception Limits

  • Humans can recognize up to about 5 objects at a single glance
  • Beyond that, we need to count or group
  • This natural limit prompted replacement of groups with new symbols

Common Group Sizes
Different cultures chose different group sizes:

  • Base-2 (groups of 2)
  • Base-5 (groups of 5)
  • Base-10 (groups of 10)
  • Base-20 (groups of 20)

Counting in groups is much more efficient than pure tally systems for large numbers.

The Idea of a Base

The concept of “base” was a major breakthrough in number systems.

I. Egyptian Number System (3000 BCE)

The Egyptians developed a system based on powers of 10.

Landmark Numbers

  • 1, 10, 10², 10³, 10⁴, 10⁵, 10⁶, 10⁷
  • Each landmark number is 10 times the previous one
  • All landmark numbers are powers of 10
  • They assigned different symbols to each power of 10

Representing Numbers
To write a number:

  • Group the number into landmark numbers starting from largest
  • Example: 324 = 100+100+100+10+10+4 = (3×100) + (2×10) + (4×1)
  • Write using appropriate symbols for each power of 10

II. Base-n Number Systems

The Egyptian system introduced an imp mathematical concept: the base.

Definition of Base-n System

  • First landmark number is always 1
  • Every next landmark number is obtained by multiplying current one by fixed number n
  • This creates a base-n number system
  • Base-10 is also called decimal number system

Example: Base-5 System
Landmark numbers are: 1, 5, 5², 5³, 5⁴, 5⁵ = 1, 5, 25, 125, 625, 3125

To represent 143 in base-5:

  • 143 = 125 + 5 + 5 + 5 + 1 + 1 + 1
  • 143 = (1×125) + (3×5) + (3×1)

Advantages of Base-n Systems

Why are base-n systems so good for mathematics?

Mathematical Properties

  • All landmark numbers are powers of the base number
  • Product of two landmark numbers is another landmark number
  • This makes multiplication much simpler
  • Distributive law applies cleanly: (a+b)×n = a×n + b×n

Example: Egyptian System Multiplication

  • Multiplying any number by 10 just adds one more symbol
  • Pattern recognition makes arithmetic operations easier
  • Systematic grouping and regrouping follows consistent rules

These properties make calculations much easier compared to systems without a base.

III. Abacus and Decimal System

The abacus shows how base-10 thinking developed into tools for calculation.

11th Century Abacus

  • Used lines representing powers of 10
  • Counters placed on lines to represent numbers
  • Counter above a line contributed value of 5
  • Addition was performed by bringing counters together
  • When total exceeded 10, it was carried to next higher power line

This carrying process is exactly what we do in modern arithmetic!

Place Value Representation

The next big innovation was place value – the idea that position of a digit determines its value.

I. Mesopotamian Number System

Ancient Mesopotamians developed one of the first positional systems.

Base-60 System

  • Later became a base-60 system (sexagesimal)
  • Base-60 choice possibly related to lunar month being about 30 days
  • Or related to astronomical cycles
  • Modern influence: 1 hour = 60 minutes, 1 minute = 60 seconds

Symbols and Representation

  • Had symbol for 1 and symbol for 10
  • Landmark numbers: 1, 60, 60², 60³, 60⁴…
  • Numbers 1-59 were represented using combinations of basic symbols
  • Compact representation possible by dropping landmark number symbols

Examples

  • 640 = (10)×60 + 40 (represented using positional notation)
  • 7530 = (2)×3600 + (5)×60 + 30
  • Rightmost symbols show 1s, next left shows 60s, next shows 3600s

Problems with This System

  • Blank spaces were used when a power of 60 was not present
  • Spacing inconsistencies created ambiguities
  • Same numeral could be read in different ways
  • Difficulty maintaining consistent spacing across manuscripts
  • Later, Mesopotamians developed a placeholder symbol (like zero) for blank spaces
  • But this placeholder was primarily used in middle of numbers, not at end

II. Mayan Number System (3rd-10th centuries CE)

The Mayans independently developed a positional system in Central America.

System Structure

  • Almost base-20 system with landmark numbers: 1, 20, 360, 7200, 144000
  • Third landmark is 360 instead of 400, possibly related to their calendar system
  • Used a placeholder symbol resembling seashell for zero

Mayan Symbols

  • Dot represented 1
  • Bar represented 5
  • Numbers 1-19 were represented using combinations of dots and bars
  • Symbols were written vertically with specific positional meaning
  • Lowermost position for 1s, above for 20s, next for 360s

Limitation
Not a true base-20 system because of the irregular third landmark (360 instead of 400), which reduced its computational advantages.

III. Chinese Number System

China developed two parallel systems for numbers.

Two Systems

  • Written system for formal documents
  • Rod-based system for calculations

Rod Numerals

  • More efficient for writing and computing
  • Developed by 3rd century AD, used until 17th century
  • Base-10 decimal system with symbols for 1-9
  • Alternated between two types of symbols (Zongs and Hengs)
  • Zongs used for units, hundreds, ten thousands
  • Hengs used for tens, thousands, hundred thousands

Advantages

  • Blank spaces indicated skipped place values
  • More uniform symbol sizes made blank spaces easier to locate than in Mesopotamian system
  • This reduced ambiguity

IV. Hindu Number System

The Hindu number system represents the culmination of thousands of years of development.

Revolutionary Features

  • Base-10 decimal place value system
  • Ten symbols: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
  • Each position represents a power of 10
  • Example: 375 = (3)×10² + (7)×10¹ + (5)×10⁰

What Made It Special

  • Zero used as both placeholder AND as a number
  • No ambiguity in reading or writing numerals
  • Single digit in each position eliminates confusion
  • Zero as a number enabled advanced mathematical computations

Mathematical Significance
Aryabhata (499 CE) used zero for elaborate scientific computations. Later, Brahmagupta (628 CE) codified the arithmetic properties of zero:

  • Zero plus any number equals the same number: 0 + n = n
  • Zero times any number equals zero: 0 × n = 0
  • This created what mathematicians call a “ring” – a set closed under addition, subtraction, and multiplication

Global Impact
The Hindu number system became:

  • Foundation for modern mathematics, algebra, and analysis
  • Basis for science, technology, computing, accounting, surveying
  • One of the greatest and most influential inventions of all time
  • Used constantly in daily life worldwide

Evolution of Ideas in Number Representation

We can see a clear progression in how number systems developed:

Five Major Stages

StageInnovationExample System
1Count in groups of single numberGumulgal (base-2)
2Group using landmark numbersRoman numerals
3Choose powers of number as landmarks (base)Egyptian system
4Use positions to denote landmark numbers (place value)Mesopotamian, Chinese
5Zero as positional digit AND as numberHindu system

Each stage built upon the previous one, adding new capabilities and making calculations easier.

Comparative Analysis

Let’s compare different systems:

Egyptian System

  • Additive system with symbols
  • No place value concept
  • Multiplication by base is easy
  • But needs many symbols for large numbers

Roman Numerals

  • Uses landmark numbers
  • More compact than pure tallying
  • Addition is possible
  • Arithmetic operations very difficult

Mesopotamian System

  • Base-60 with positional notation
  • More compact representation
  • But ambiguous without consistent zero
  • Spacing problems created confusion

Mayan System

  • Base-20 with vertical notation
  • Had zero as placeholder
  • Not true base-20 (irregular landmarks)
  • Limited computational advantages

Chinese Rod System

  • Base-10 positional notation
  • Alternating symbols reduced ambiguity
  • Blank spaces for missing place values
  • More reliable than Mesopotamian

Hindu System

  • Fully developed base-10 positional
  • Zero as both digit and number
  • No ambiguity at all
  • Perfect for all arithmetic operations
  • Foundation of modern mathematics

The Hindu system combined all the best features while eliminating the problems of earlier systems.

Why Does This Matter?

Understanding the history of numbers helps us appreciate what we have today. Every time you write “0” or easily multiply large numbers, you’re using a system that took humanity thousands of years to develop.

The Hindu number system was so superior that once people learned it, they gradually abandoned their old systems. This wasn’t because of conquest or force – it was simply because it worked better. That’s the power of a truly good mathematical idea.

Modern Life Connection

  • Every calculator uses this system
  • Every computer internally uses similar positional concepts
  • All scientific calculations depend on it
  • Global commerce relies on it
  • Even the way we think about mathematics is shaped by it

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