In short: NCERT textbooks should always be your primary study material for CBSE board exams because over 80% of questions come directly from NCERT content. Reference books like RD Sharma, RS Aggarwal, HC Verma, and Selina add value only when used selectively for extra practice after you have finished NCERT. The biggest mistake is buying five reference books and completing none of them.
Walk into any bookshop near a school in India and you will see shelves overflowing with reference books for every class and every subject. Parents and students load up on RD Sharma, RS Aggarwal, Lakhmir Singh, Selina, HC Verma, and Arihant guides hoping that more books mean better preparation.
That assumption is almost always wrong. This guide gives you an honest, subject-wise breakdown of when NCERT is enough, when you genuinely need a reference book, and how to balance both without wasting time.
The 80/20 Rule of Board Exam Preparation
Here is a fact that catches most students off guard: over 80% of CBSE board exam questions are directly based on NCERT content. Definitions, in-text questions, solved examples, diagrams, and end-of-chapter exercises form the backbone of every question paper.
A student who reads NCERT thoroughly, solves every exercise, and understands every concept already has the foundation to score well above 80% in boards. Reference books help push from 80% to 95% and beyond, but only when the NCERT base is already solid.
The problem surfaces when students skip NCERT and jump straight into reference books. RD Sharma problems are harder than board-level questions. HC Verma Physics assumes deeper understanding than the syllabus demands. Without the NCERT foundation, reference book study becomes confusing and counterproductive.
Think of it this way: NCERT builds the house, reference books add the finishing touches. You cannot paint walls that do not exist yet. For a detailed reading strategy, check out our guide on how to read NCERT effectively for board exams.
Subject-Wise Breakdown: When NCERT Is Enough
Not every subject needs a reference book. Here is a realistic assessment for Class 10 and Class 12 board exams.
Mathematics
Maths is the one subject where a reference book genuinely adds value at every level. NCERT Maths provides clear explanations and decent exercises, but board exam papers sometimes include problems that are slightly trickier than NCERT examples.
For Class 10 Maths, RD Sharma or RS Aggarwal gives the extra practice you need. Focus on NCERT first. Solve every exercise and example. Then use the reference book for additional problems in high-weightage chapters like Real Numbers, Quadratic Equations, Trigonometry, and Statistics. You do not need to complete the entire reference book. For a formula quick-reference to study alongside, see our complete list of CBSE Class 10 Maths formulas.
For Class 12 Maths, the same principle applies. NCERT is your primary source, and RD Sharma helps with chapters like Integration, Probability, and 3D Geometry where practice volume matters.
Science (Physics, Chemistry, Biology)
For Class 10 Science, NCERT is largely sufficient. The textbook covers every concept that the board exam tests. Lakhmir Singh is popular, but most of its content overlaps with NCERT. The additional value comes from extra numerical problems in Physics and diagram-based questions in Biology.
If you pick Lakhmir Singh, use it selectively. Do not re-read the theory sections because NCERT theory is what examiners expect. Use it only for extra practice questions in chapters like Electricity, Light, and Chemical Reactions. To understand how marks are distributed, see our CBSE Class 10 Science chapter-wise marks weightage guide.
For Class 12 Physics, HC Verma is excellent but aimed more at competitive exams. For board preparation alone, SL Arora is more aligned with CBSE patterns. For Chemistry, NCERT is almost always sufficient. For Biology, NCERT diagrams and specific terminology are what examiners look for.
Social Science
NCERT is completely sufficient for Social Science at both Class 10 and Class 12 levels. You do not need any reference book. Board exam answers in Social Science are expected to follow NCERT language, and using unfamiliar terminology from reference books can actually confuse examiners and cost you marks.
English
NCERT plus supplementary readers (Footprints Without Feet, Vistas) cover the literature portion. For grammar and writing, practice from previous year papers is more useful than any grammar reference book. The English board exam tests comprehension and expression, not obscure rules.
Hindi and Other Languages
NCERT textbooks are sufficient. Focus on reading chapters carefully, understanding themes, and practicing writing formats from previous year papers.
The Biggest Mistake: Buying Five Books, Finishing None
This is the most common trap in Indian exam preparation. A student buys RD Sharma, RS Aggarwal, Lakhmir Singh, Together with Science, and an Arihant guide, all for the same subject. The result? They open each book once, feel overwhelmed, and end up studying none of them properly.
This is worse than having no reference books at all. Time spent browsing multiple books and comparing explanations creates an illusion of studying without actual learning. For more such pitfalls, read our guide on common mistakes in board exam preparation.
The fix is simple: choose a maximum of one reference book per subject (and only for subjects that need it), and commit to finishing relevant chapters from that one book.
When Reference Books Actually Help
Reference books are genuinely useful in a few specific situations.
When you need more practice problems. NCERT Maths has around 15 to 20 problems per exercise. For mastering a chapter like Trigonometry or Integration, you might need 40 to 50 problems. A reference book provides that volume.
When you want exposure to different question styles. Board exams occasionally include questions framed differently from NCERT exercises. Reference books expose you to varied formats, which helps with surprises in the actual paper.
When you are preparing for competitive exams alongside boards. If you are working towards JEE or NEET along with Class 12 boards, reference books and coaching material are necessary because competitive exams test deeper than board level. But for boards alone, NCERT remains the primary source.
When a specific NCERT explanation is unclear. Sometimes the NCERT text on a topic is too brief or abstract. A reference book might explain the same concept with more examples. Use it as a secondary explanation, not a replacement.
How to Balance NCERT and Reference Books Effectively
The ideal approach combines both resources strategically rather than treating them as separate study tracks.
Step 1: Start Every Chapter with NCERT
Read the NCERT chapter first. Understand the theory, study solved examples, and attempt every exercise question. This builds your foundation and aligns your thinking with how the board exam is framed.
Step 2: Identify Weak Areas
After finishing the NCERT chapter, note topics where you feel unsure or made mistakes in exercises. These are the areas where a reference book adds real value.
Step 3: Use the Reference Book Selectively
Open the reference book only for the weak topics you identified. Do not re-read the theory. Go straight to practice problems and work through them. The goal is additional practice, not additional reading.
Step 4: Return to NCERT for Revision
During revision, always go back to NCERT. Your margin notes, highlights, and solved exercises in NCERT are your revision material. The reference book is for practice, not for last-minute review. For a complete revision approach, see our best revision strategy before board exams.
This method ensures you spend roughly 80% of your time on NCERT and 20% on targeted reference book practice.
Popular Reference Books: Quick Recommendations
Here is a concise list of the most commonly used and trusted reference books by subject.
For Class 10 Maths: RD Sharma (comprehensive, more problems per chapter) or RS Aggarwal (concise, exam-focused). Pick one, not both.
For Class 10 Science: Lakhmir Singh for extra practice questions. Skip the theory sections entirely.
For Class 12 Physics: SL Arora for board preparation. HC Verma for JEE overlap.
For Class 12 Chemistry: NCERT is enough for boards. MS Chauhan for extra organic chemistry practice if needed.
For Class 12 Biology: NCERT is almost always sufficient. Trueman's Biology is a common supplement.
For Class 12 Maths: RD Sharma remains the standard choice.
For ICSE students: Selina is the go-to reference for Maths and Science. It aligns closely with the ICSE pattern and provides well-structured practice problems.
How NCERT Exemplar Fits In
Many students overlook NCERT Exemplar books. Published by NCERT itself, Exemplar contains higher-order thinking questions that are more challenging than regular NCERT exercises but perfectly aligned with the CBSE pattern.
For students aiming above 90%, NCERT Exemplar is arguably more valuable than any third-party reference book. It bridges the gap between NCERT exercises and board-level tricky questions without introducing unnecessary content. The problems are designed specifically to test conceptual clarity, which is exactly what competency-based questions in recent CBSE papers demand.
The Bottom Line
NCERT is your primary study material for any board exam, especially CBSE. It covers 80% or more of what the exam tests. Reference books add value only when used selectively and strategically, on top of a solid NCERT foundation.
Do not fall into the trap of collecting books. A student who finishes NCERT thoroughly and solves previous year papers will almost always outscore a student who half-reads three reference books. Depth beats breadth in board exam preparation.
Frequently Asked Questions
Is NCERT really enough for scoring 90% in boards?
Yes, for most subjects. Thorough understanding of NCERT content combined with previous year papers and CBSE sample papers is sufficient to reach 90%. The key word is "thorough," meaning reading every line, solving every exercise, and understanding every diagram. For Maths, adding one reference book for extra practice helps push your score further.
Which is better for Class 10 Maths: RD Sharma or RS Aggarwal?
Both are excellent. RD Sharma has more problems per chapter and deeper explanations. RS Aggarwal is more concise and exam-oriented. If you are short on time, RS Aggarwal is more efficient. If you have time for thorough practice, RD Sharma is better. Choose one and commit to it.
Should I buy Lakhmir Singh for Science if I already have NCERT?
Only if you want additional practice questions, especially for Physics numericals and Biology diagrams. Do not use Lakhmir Singh for theory because NCERT theory is what the board exam expects. A better alternative might be solving CBSE sample papers for Science, which give practice in the exact exam format.
Can I skip NCERT and study only from reference books?
This is one of the most common and costly mistakes. Reference books often use different terminology and present concepts in ways that do not match how CBSE examiners frame questions. Students who skip NCERT frequently lose marks because their answers lack the expected language and structure. Always start with NCERT.
How does Selina compare to RD Sharma for ICSE students?
Selina is specifically designed for the ICSE curriculum and follows the ICSE question pattern closely. RD Sharma, while comprehensive, is more CBSE-oriented. ICSE students should prefer Selina as their primary reference book for both Maths and Science because it matches their board's expectations.
The most effective strategy is straightforward: master NCERT, add targeted reference book practice for Maths, and test yourself with previous year papers. If you want an AI-powered way to practice NCERT-aligned questions chapter by chapter, try Padhaao. It follows your syllabus, adapts to your level, and helps you focus on exactly what the exam demands.
Want the full chapter with solved examples?
10 learning modes. Board-specific content. 3 free chapters every day.
Try it free