Story of Numbers Class 8 Notes: Full Chapter Explained (2026)

eSaral ›Foundation courses ›Story of Numbers Class 8 Notes: Full Chapter Explained (2026)

🚀 Checkout eSaral Courses

Introduction

Imagine every number suddenly disappearing overnight. You wouldn't know the time to leave for school, the score on your phone game, or even the price of a ₹10 chips packet. Now push that thought back thousands of years, to when humans lived in caves. How did they count their goats, track how many rotis were made, or mark the passing of days?

This is exactly the question the Story of Numbers chapter answers. It might look like a "boring" theory chapter because it has no addition or subtraction, but it is packed with exam-relevant facts about how counting systems developed — from scratch marks on animal bones to the Hindu place-value system we use today.

Let's go through each counting method the way it actually developed, step by step.

Why Did Early Humans Need Counting Methods? 

Before written numbers existed, humans still needed to track their cattle, food supplies and the changing seasons. Stone Age humans solved this using physical objects and body-based counting rather than symbols.

The physical method: People used pebbles, sticks or shells to represent items. For example, if someone owned 40 cows, they would place one stick for each cow. If a stick was left without a cow standing in front of it, they immediately knew that particular cow was missing.

Sound and name-based methods: Some groups used specific sounds or letters to represent counts instead of physical objects.

Tally marks: A simple line-based method — drawing one mark (I) per item, such as I, II, III, IIII — was another common early technique.

Body-part counting: Just as we count 1 to 10 on our fingers today, some early counting systems used up to 27 body parts to build a complete counting sequence.

💡 Expert Tip: These early counting methods — the physical (stick/pebble/shell) method, tally marks, and body-part counting — are commonly asked as direct one-line answers in exams, so remember all three by name.

Extending the Number System Using Letters 

A classic textbook question asks how a letter-based system (A = 1, B = 2, C = 3...) could be extended once you run out of the 26 alphabet letters.

The answer: after Z (26), you can start doubling letters — AA, BB, CC represent 27, 28, 29 and so on up to 52. Once double letters are exhausted, you can move to triple letters — AAA represents 53, BBB represents 54 — and this pattern can continue indefinitely to represent any number.

Physical Notches on Hard Surfaces: Ishango and Lebombo Bones

One of the oldest known methods of recording numbers was scratching a physical notch onto a hard surface — similar to how a stone dragged along a car door leaves a permanent scratch line.

Two specific bones are named in this chapter for this purpose:

Both bones carry scratch marks that historians believe were used for counting, making them among the earliest physical evidence of number recording.

The Grouping Method: Australian Aboriginal Counting

Some Aboriginal Australian communities used a "grouping by two" method, giving distinct names only to the numbers one and two, and building every other number by combining them:

This shows how a counting system can be built from just two base words by combining them repeatedly.

The Roman Number System

The Roman number system is one of the most widely used historical systems, but it had one major limitation — it had no symbol for zero.

Converting Numbers to Roman Numerals

To write 2367 in Roman numerals: split it into 2000 + 300 + 60 + 7 → MM + CCC + LX + VII = MMCCCLXVII.

To write a number where the thousands, hundreds, tens and ones digits are each 1, 2, 2 and 2 respectively: M + CC + XX + II = MCCXXII.

Converting Roman Numerals to Numbers

LXX breaks down as L(50) + X(10) + X(10) = 70.

Solved Example: Ankita's Shopping Bill

Ankita paid DCCCXV rupees for a school bag and a pencil box together.

• D = 500, C = 100, C = 100, X = 10, V = 5 → Total = ₹815

The cost of the pencil alone was CLXII:

• C = 100, L = 50, X = 10, I = 1, I = 1 → ₹162

So, cost of the school bag = 815 − 162 = ₹653, written in Roman numerals as DCLIII (D=500, C=100, L=50, III=3).

💡 Expert Tip : A Roman numeral conversion question comes up almost every year in the exam — practice both directions (Roman to number and number to Roman) until they're automatic.

The Egyptian Number System 

The Egyptian system was also a base 10 system, but it used picture symbols instead of digits.

Solved example: To write 10,458, you would use 1 pointing finger (10,000) + 4 coiled ropes (400) + 5 heel bones (50) + 8 strokes (8).

Drawbacks of the Egyptian system: Large or repetitive numbers like 99 needed up to 36 separate symbols, making them extremely tedious to write. There was no place value system and — most critically — no symbol for zero, which eventually made this system impractical for advanced calculations.

The Babylonian (Mesopotamian) Number System 

The Babylonian system, also called the Mesopotamian number system, was a base 60 system.

Numbers 1 to 9 were shown using vertical wedge marks, 10 was shown with an angled wedge, and combinations of these represented values up to 59 — similar in spirit to the additive style of Roman numerals. Distinct symbols marked the landmark values of 60¹, 60² and 60³.

This system introduced place value, marking real progress over the Egyptian system. However, it still required building very large combinations of symbols for bigger numbers, which limited its practicality.

💡 Expert Tip : A common exam question asks which system is also known as "Babylonian" — the answer is the Mesopotamian system; both names refer to the same base-60 system.

Mayan and Chinese Number Systems 

The Mayan system used a base 20 structure with three basic symbols:

The Chinese rod numeral system was a base 10 system that used two alternating symbol sets — called Zong and Heng — for alternating place values. Zong symbols represented the units, hundreds, ten-thousands and so on, while Heng symbols represented the tens, thousands, hundred-thousands and so on. Each place value alternated between vertical (Zong) and horizontal (Heng) rod arrangements, allowing numbers like 346,298 to be built digit by digit using this alternating pattern.

The Hindu Number System and the Power of Zero

The Hindu number system is the one used globally today — a base 10 decimal place-value system built from just 10 unique symbols: 0 to 9.

The most important contribution of this system was zero, which is credited in this chapter to Indian mathematicians such as Brahmagupta. Zero acts as a placeholder, allowing us to distinguish between numbers like 5, 50 and 500 — something the Egyptian and Roman systems could never do without a huge number of extra symbols.

Why Is the Hindu Number System More Efficient Than Roman Numerals?

The Hindu number system has zero and full place value, which the Roman numeral system does not. This single feature made it far more suitable for positional writing of numbers and complex arithmetic, which is why it eventually replaced Roman and Egyptian systems worldwide.

What Does "Base n" Mean in a Number System?

A base n number system uses landmark numbers that are strictly powers of n, which simplifies arithmetic significantly. The Egyptian system, for example, was an early base 10 system where every landmark symbol represented a power of 10 (1, 10, 100, 1,000...).

Solved Example: Expressing 143 in Base Five

In base five, the landmark values are powers of 5: 5⁰=1, 5¹=5, 5²=25, 5³=125.

143 = 1×125 + 0×25 + 3×5 + 3×1, which means 143 in base five is written using one 5³ term, three 5¹ terms and three 5⁰ terms.