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CBSE Class 10 Science and Maths weightage 2026-27: unit marks and what each chapter carries

CMDLearn · 3 November 2026

The short answer: CBSE publishes marks for each unit, not for each chapter. For 2026-27:

• Science theory paper: Unit I 25, Unit II 25, Unit III 12, Unit IV 13 and Unit V 5 marks.
• Maths theory paper: Number Systems 6, Algebra 20, Coordinate Geometry 6, Geometry 15, Trigonometry 12, Mensuration 10, and Statistics and Probability 11.

Each paper totals 80, and internal assessment at school adds 20.

Chapter-wise "weightage" tables you find online are someone's estimate. Below we give:

• the official unit marks;
• the chapters in each unit;
• one thing you can check yourself: how many marks each chapter actually got in CBSE's own 2026-27 sample papers.

We counted every question. Those counts are labelled "in the sample paper", because that is all they are.

What CBSE publishes, and what it does not

Published:

• unit marks for the 80-mark theory paper (Science curriculum, page 4; Maths curriculum, page 3);
• the 20 marks of internal assessment (Science, page 4; Maths, pages 8-9);
• the topics in each unit;
• the question paper design (Science, page 9; Maths, pages 8-9);
• one sample question paper with a marking scheme for Science, and two for Maths (Standard and Basic).

Not published: marks for each chapter.

• Neither curriculum gives chapter marks, and neither sample paper labels its questions by chapter.
• The curricula do not even number the chapters. Our mapping of chapters to units below follows the topics each unit lists, as in our Science syllabus guide and Maths syllabus guide.

So no one can tell you that "Electricity is worth 7 marks" in the board exam. They can only tell you that Unit IV is worth 13 marks, and that Electricity is one of its two chapters.

Science: unit marks and the 2026-27 sample paper

The theory paper is 3 hours and 80 marks (curriculum, page 4). The sample paper has 39 questions in three sections: Section A is Biology, B is Chemistry and C is Physics (sample paper, page 1).

Every unit total in the sample paper matches the curriculum exactly: 25, 25, 12, 13 and 5. Inside a unit, though, the split between chapters is up to whoever sets the paper.

• Life Processes alone carries 11 of Unit II's 25 marks, mostly through a 5-mark question on the heart and breathing (Q16).
• Acids, Bases and Salts carries only 4 of Unit I's 25 marks.

Taught, but not in the board paper. The curriculum says these topics are assessed only at school ("formatively"), so they carry no board marks:

• periodic classification of elements (page 4);
• the evolution topics (page 5);
• the electric motor, electromagnetic induction and the electric generator (page 6).

Our Science syllabus guide lists these topics in full. It also covers the page-6 note for teachers, which is best read with your teacher.

Maths: unit marks, Standard and Basic

Mathematics Standard (041) and Mathematics Basic (241) use the same seven units and the same unit marks (curriculum, page 3). Each paper has 38 questions in five sections, worth 20, 10, 18, 20 and 12 marks (sample papers, page 1).

Again, every unit total in both sample papers matches the curriculum: 6, 20, 6, 15, 12, 10 and 11. The split between chapters is different in the two papers:

• Arithmetic Progressions gets 4 marks in Standard and 6 in Basic, because Basic's 4-mark case study is about an AP (Basic Q37).
• Polynomials gets 5 marks in Standard and 3 in Basic.

How we counted (so you can check it)

• One question, one chapter. We read every question in the three sample papers and placed it under the NCERT chapter whose method it tests. The marks are CBSE's own: each is printed next to its question and in the marking schemes.
• Internal choice. Where a question offers "OR" options, we counted the first one. In all three papers, both options of every choice question come from the same chapter, with one exception: - Science Q29: option A is all from Chemical Reactions and Equations, but one part of option B (aluminium in dilute acid) is from Acids, Bases and Salts or Metals and Non-metals.
• Split question. Science Q27 has three 1-mark parts (marking scheme, Q27). We placed: - (A), electrolytes conducting, and (C), rusting by the sea, under Metals and Non-metals; - (B), lime water clearing with excess carbon dioxide, under Acids, Bases and Salts.
• One judgement call: Basic Q13. It is about a ladder reaching a window, and you solve it with Pythagoras' theorem; no angle is given. - The current Triangles chapter no longer teaches that theorem, but Introduction to Trigonometry uses it, so we placed Q13 under Trigonometry. - That is also the only placement that makes the Basic paper's unit totals match the curriculum.
• The check. A script adds up the marks and checks three things: - each paper totals 80; - each Maths section adds up to the marks the paper states; - every unit total equals the curriculum's unit marks.

All three checks pass.

How to use this

1. Plan by unit first. Unit marks are official, so give your time in proportion to them. In Science, Units I and II carry 50 of the 80 marks. In Maths, Algebra (20) and Geometry (15) together carry 35.
2. Treat the sample-paper counts as a hint only. They show what one paper did. A board paper can split a unit's marks differently between its chapters; only the unit total is fixed.
3. Do not drop a chapter because it got few marks here. Acids, Bases and Salts got 4 marks in this paper, but a board paper could give it a 5-mark question.
4. Practise chapter by chapter. Each chapter above links to our questions with answers. For whole papers, see our guides to the Science sample paper, the Maths Standard sample paper and the Maths Basic sample paper.

Where CMDLearn fits

CMDLearn is building an AI tutor for Classes 1 to 10 that explains a step and checks the child's working, but leaves the writing to the child. It is still in development, and no child uses it yet. If you would like to hear when there is something to try, you can join the waitlist.

Sources

All fetched and checked on 3 November 2026.

• CBSE, Science (086), Class X, 2026-27, curriculum: page 4 (course structure, unit marks, internal assessment 20, Unit I formative topics), page 5 (Unit II, evolution formative), page 6 (Units III to V, motor and generator formative), page 9 (question paper design). cbseacademic.nic.in/web_material/CurriculumMain27/SecPart1/Science_SecP1_2026-27.pdf
• CBSE, Mathematics, Class X, 2026-27, curriculum: page 3 (course structure, unit marks), pages 3-7 (unit topics), pages 8-9 (question paper design and internal assessment, Standard and Basic). cbseacademic.nic.in/web_material/CurriculumMain27/SecPart1/Maths_SecP1X_2026-27.pdf
• CBSE, Science (086) Sample Question Paper, Class X, 2026-27, pages 1-15, and its marking scheme. cbseacademic.nic.in/web_material/SQP/ClassX_2026_27/Science-SQP.pdf and cbseacademic.nic.in/web_material/SQP/ClassX_2026_27/Science-MS.pdf
• CBSE, Mathematics Standard (041) Sample Question Paper, Class X, 2026-27, pages 1-6, and its marking scheme. cbseacademic.nic.in/web_material/SQP/ClassX_2026_27/MathsStandard-SQP.pdf and cbseacademic.nic.in/web_material/SQP/ClassX_2026_27/MathsStandard-MS.pdf
• CBSE, Mathematics Basic (241) Sample Question Paper, Class X, 2026-27, pages 1-8, and its marking scheme. cbseacademic.nic.in/web_material/SQP/ClassX_2026_27/MathsBasic-SQP.pdf and cbseacademic.nic.in/web_material/SQP/ClassX_2026_27/MathsBasic-MS.pdf
• NCERT, Science, Textbook for Class X and Mathematics, Textbook for Class X (Reprint 2026-27): chapter titles, from the contents pages. ncert.nic.in/textbook/pdf/jesc1ps.pdf and ncert.nic.in/textbook/pdf/jemh1ps.pdf

The unit marks, question marks and paper designs are CBSE's. Placing chapters under units, placing each sample-paper question under a chapter, and the advice are ours. CBSE does not publish chapter weightage; always follow your school and CBSE's official notices.

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