Punjab Board 2027 Syllabus

Class 9 Mathematics Β· Chapter 2

Chapter 2: Logarithms

Class 9 Math Chapter 2 notes with solved exercises, definitions, formulas, MCQs, and review exercises covering scientific notation and laws of logarithms.

Prepared by Muhammad Tayyab
Scientific Notation Common Logarithms Laws of Logarithms Exponential Equations Characteristic & Mantissa
4 Exercises
7 Key Definitions
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Class 9 Math Chapter 2: All Notes & Resources

Choose a resource below for Chapter 2 Logarithms, from solved exercises to definitions and MCQs.

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Class 9 Mathematics Chapter 2 introduces logarithms, a powerful mathematical tool used to solve complex exponential equations and simplify calculations. You will explore scientific notation, common and natural logarithms, and the fundamental laws of logarithms. This hub gathers every Chapter 2 resource in one place. Start with the Chapter 2 definitions for quick revision, then move to the solved exercises below. For targeted practice, try the Chapter 2 MCQs. You can also review the Grade 9 Math Pairing Scheme to understand paper weightings. When you are done, return to the main Class 9 Mathematics page for the next chapter.

Last updated: October 22, 2026

Exercise

Exercise 2.1 Solved

Express numbers in scientific and ordinary notation, and calculate standard form for real-world values like the diameter of Mars or speed of light.

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Exercise

Exercise 2.2 Solved

Convert between logarithmic and exponential forms, and find the value of unknown variables in logarithmic equations.

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Exercise

Exercise 2.3 Solved

Find the characteristic and mantissa of numbers, evaluate logarithms using tables, and solve problems involving antilogarithms.

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Exercise

Exercise 2.4 Solved

Apply the laws of logarithms to evaluate expressions without a calculator, expand and combine logs, and solve real-world exponential equations.

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Definitions

Chapter 2 Definitions

All key definitions including scientific notation, common and natural logarithms, characteristic, mantissa, and antilogarithm.

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MCQs

Chapter 2 MCQs

Multiple-choice questions covering the entire chapter with detailed solutions, perfect for exam preparation and self-testing.

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Subject Specialist Math

MSc Mathematics Β· Govt Christian High School Daska, Sialkot, Punjab

Last updated: October 22, 2026

Key Concepts – Logarithms

Logarithmic Form
\(\log_b x = y \iff b^y = x\)

The logarithm of \(x\) to the base \(b\) is the exponent \(y\) to which \(b\) must be raised to get \(x\).

Product Law
\(\log_b(mn) = \log_b m + \log_b n\)

The logarithm of a product is the sum of the logarithms of the factors.

Quotient Law
\(\log_b\left(\frac{m}{n}\right) = \log_b m - \log_b n\)

The logarithm of a quotient is the difference of the logarithms.

Power Law
\(\log_b(m^n) = n \log_b m\)

The logarithm of a number raised to a power is the power times the logarithm of the number.

Change of Base
\(\log_b x = \frac{\log_a x}{\log_a b}\)

Allows calculating logarithms in any base using a different base (like 10 or \(e\)).

Scientific Notation
\(a \times 10^n\)

A number written as a coefficient \(a\) (where \(1 \leq a < 10\)) multiplied by a power of 10.

Chapter 2 Frequently Asked Questions

What is a logarithm?

A logarithm answers the question: "To what power must the base be raised to get a certain number?" For example, \(\log_2 8 = 3\) because \(2^3 = 8\).

What is the difference between common and natural logarithms?

Common logarithms have a base of 10 (written as \(\log\) or \(\log_{10}\)), while natural logarithms have a base of \(e\) (written as \(\ln\)).

What are characteristic and mantissa?

In a logarithm, the integral part is the characteristic (which determines the number of digits) and the decimal part is the mantissa (which determines the significant digits).

How do I convert between exponential and logarithmic form?

Use the relationship \(b^y = x \iff \log_b x = y\). For example, \(10^2 = 100\) is equivalent to \(\log_{10} 100 = 2\).

Why are logarithms useful in real life?

Logarithms simplify complex calculations involving large numbers, such as measuring earthquake magnitudes (Richter scale), sound intensity (decibels), and calculating compound interest or population growth.

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