DRISHTI IAS Basic Numeracy – GS (P+M) Foundation Course | For Civil Services Examination

• Comprehensive coverage of Basic Numeracy for Civil Services Examination preparation
• Covers Number System & Simplification from basic concepts to number types and calculations
• Includes H.C.F. & L.C.M. with factorisation and division methods
• Covers Average & Percentage with formulas, shortcuts and application-based questions
• Detailed coverage of Profit & Loss, Cost Price, Selling Price, Marked Price and Discount
• Includes Ratio, Proportion & Mixture
• Covers Simple Interest & Compound Interest
• Detailed section on Time & Work, Efficiency and Work & Wages
• Includes Time, Distance & Speed with Average Speed and motion-based concepts
• Covers Fundamentals of Algebra and Linear Equations
• Includes Series, Arithmetic Progression and Geometric Progression
• Covers Set Theory
• Includes Permutation & Combination
• Covers Probability
• Detailed coverage of Mensuration
• Includes Height & Distance with basic Trigonometry
• Designed as part of a GS (P+M) Foundation Course for Civil Services Examination

The uploaded PDF is titled Basic Numeracy and is presented as part of a GS (P+M) Foundation Course for Civil Services Examination.

About this Book

Drishti IAS Basic Numeracy is a structured quantitative aptitude resource designed for aspirants preparing for the Civil Services Examination, especially for developing core numerical and calculation-based skills.

The book covers 15 major chapters, starting with Number System & Simplification and progressing through H.C.F. & L.C.M., Average, Percentage, Profit & Loss, Ratio & Proportion, Mixture, Interest, Time & Work, Time-Speed-Distance, Algebra, Series, Set Theory, Permutation & Combination, Probability, Mensuration, and Height & Distance.

The material combines concept explanations, formulas, examples and calculation techniques, making it useful for learners who want to strengthen their basics and improve speed and accuracy in numerical questions.

Key Areas Covered

• Number System
• Simplification
• Natural, Whole, Even, Odd & Prime Numbers
• Integers
• H.C.F.
• L.C.M.
• Average
• Percentage
• Profit & Loss
• Marked Price & Discount
• Ratio
• Proportion
• Mixture
• Simple Interest
• Compound Interest
• Time & Work
• Work Efficiency
• Work & Wages
• Time, Distance & Speed
• Average Speed
• Linear Equations
• Arithmetic Progression
• Geometric Progression
• Set Theory
• Permutation
• Combination
• Probability
• Mensuration
• Triangles
• Area, Perimeter & Volume
• Trigonometry
• Height & Distance
• Angle of Elevation
• Angle of Depression

Table of Contents

1. Number System & Simplification

The book begins with the Decimal Number System, face value, positional value and different types of numbers.

It covers:

Natural Numbers • Whole Numbers • Even Numbers • Odd Numbers • Integers • Prime Numbers.

The chapter builds the numerical foundation required for later arithmetic topics.

2. H.C.F. & L.C.M.

The book explains the concept of Highest Common Factor (H.C.F.) and methods for finding it.

Methods covered include:

Prime Factorisation Method • Factorisation Method • Division Method.

These methods are demonstrated with numerical examples for faster calculation.

3. Average

Average is explained as the value obtained by dividing the sum of observations by the total number of observations.

The chapter includes practical results related to:

Combined Average • Change in Average • Successive Natural Numbers • Even Numbers • Odd Numbers.

4. Percentage

The chapter defines percentage as a value expressed per hundred and explains percentage increase, decrease and conversions between fractions and percentages.

It also covers Successive Percentage Change and shortcuts for reducing lengthy calculations.

5. Profit & Loss

The book covers:

Cost Price • Selling Price • Profit • Loss • Marked Price • Discount • Profit Percentage • Loss Percentage.

It also provides techniques for choosing useful assumed values to simplify Profit & Loss questions.

6. Ratio & Proportion

The section explains Ratio as a comparison between two quantitative amounts and Proportion as equality between two ratios.

It includes:

Mean Proportion • Third Proportion • Fourth Proportion • Direct Proportion • Inverse Proportion.

7. Mixture

The Mixture chapter explains how two or more items of different values can be combined in a particular ratio.

The book includes the Rule of Mixture / Alligation-style approach for determining the ratio of cheaper and costlier items and also covers repeated replacement-type questions.

8. Simple & Compound Interest

The book distinguishes:

Simple Interest – Interest calculated only on the principal
Compound Interest – Interest calculated on principal plus accumulated interest.

It includes formulas and examples for yearly and half-yearly interest calculations.

9. Time & Work

The PDF specifically describes Time & Work as an important chapter from the CSAT point of view and emphasises conceptual clarity and practice.

The core relationship is:

Work = Rate of Work × Time.

The chapter also covers:

Multiple People Working Together • Work Efficiency • Work & Wages.

10. Time, Distance & Speed

The book covers the fundamental relationship between Distance, Speed and Time, along with motion and average speed.

The text also notes that these concepts are useful for direction analysis and motion-related graphs in reasoning.

11. Fundamentals of Algebra

The chapter begins with Linear Equations and explains one-variable and two-variable equations.

It also covers different cases of equation pairs and three solving methods:

Elimination Method • Substitution Method • Cross-Multiplication Method.

12. Series

The book introduces Series as sequences following a specific rule.

It includes:

Arithmetic Progression (AP) • nth Term • Sum of AP • Geometric Progression (GP).

13. Set Theory

The Set Theory section defines a set as a well-defined collection of objects and introduces basic notation and representation methods.

It covers:

Roster Method • Set-Builder Method • Null/Empty Set • Standard Number Sets.

14. Permutation & Combination

The chapter begins with Factorials and then introduces Permutations as different arrangements of objects.

It includes formulas and solved examples related to arranging selected objects.

15. Probability

Probability begins with the distinction between:

Determinative Experiments • Random Experiments.

It covers:

Sample Space • Event • Simple Event • Complex Event • Mutually Exclusive Events.

16. Mensuration

The book explains:

Area • Perimeter • Volume • Two-Dimensional Figures • Triangle Measurement.

The triangle section includes basic area formulas and Heron’s Formula, as well as area using two sides and the included angle.

17. Height & Distance

The final section uses basic Trigonometry to understand relationships between sides and angles and to calculate heights and distances.

The chapter specifically covers:

Angle of Elevation • Angle of Depression • Line of Sight • Height-Distance Applications.

Suitable For

UPSC CSAT • Civil Services Examination • Basic Numeracy • Quantitative Aptitude • GS Foundation Course • CSAT Maths • Number System • Percentage • Ratio • Time & Work • Time Speed Distance • Algebra • Probability • Mensuration