CBSE Class 10 · Maths and Science

How CBSE examiners mark Class 10 answers

Board answers are marked in steps, not only on the final line. Here is what earns marks, where marks are lost, and three worked examples from past CBSE papers and their marking schemes.

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Marks are given for steps

A Class 10 board answer worth 2, 3 or 5 marks is not marked as simply right or wrong. The marking scheme breaks it into value points, and each value point carries part of the marks. Marks are attached to specific points in your answer, not shared out equally: in one 3-mark answer, one step can carry 1 mark and another only ½. Writing the correct formula usually earns a step mark, even if a later step goes wrong.

A mistake is charged once. CBSE’s general instructions to examiners say: No marks to be deducted for the cumulative effect of an error. It should be penalized only once. If you slip early and then work correctly from the wrong value, the later steps can still earn their marks.

Your own method counts. The same instructions say the scheme carries only suggested value points and that the students can have their own expression and if the expression is correct, the due marks should be awarded accordingly. Examiners are also told: Please do not hesitate to award full marks if the answer deserves it.

See it on a real answer sheet

A Class 10 student photographs his written answer and sees exactly where he lost ½ mark.

Swajeet, a Class 10 student, holding up his marked answer
Read the transcript

I was shocked to see the results. My name is Swajeet and I'm studying in Class 10. You can submit your subjective answers by taking a photo. I saw that not only were my objectives corrected instantly, but even my subjective answers were graded. They were graded according to the marking scheme, and I could see where exactly I went wrong. I solved a problem without writing the formula, and for that I lost half a mark. It showed me some analysis, and it said that these are your weak topics. "Let's focus on these," and it gave me a set of questions to practise. It's a really good all-in-one solution for us.

Where marks are lost

  • The formula. Start with the formula. It often earns a mark on its own.
  • Units. Write the unit with your final answer. CBSE marking schemes often mark down answers that leave it out.
  • The final answer. The last line is a value point of its own. A wrong final answer costs that point; the steps above it keep the marks they earned.
  • Working not shown. Step marks can only go to steps that are on the page. A bare final answer that is wrong leaves nothing to give marks to.
  • Diagrams. The drawing and its labels are often marked separately, so a diagram with missing labels or missing arrows can lose marks.
  • Chemical equations. An unbalanced equation loses marks, even when the chemicals in it are right.
  • Everyday words. Use the scientific term from your NCERT book (oesophagus, not 'food pipe'). Examiners look for the right terms.

Three worked examples from past papers

Each is a real CBSE Class 10 board question with its marking scheme, abbreviated. The marks on the right are the scheme’s.

Maths · 2 marks · CBSE 2024, paper 30/5/1, Q21(a)

If two tangents inclined at an angle of 60° are drawn to a circle of radius 3 cm, then find the length of each tangent.

The marking scheme

  1. Correct figure½
  2. ∠APO = 30°½
  3. tan 30° = 1/√3 = 3/AP½
  4. AP = 3√3 cm½

Source: CBSE Marking Scheme 2024, Mathematics (041), paper 30/5/1, Q21(a)

This scheme gives each line its own half mark. The figure and the angle are worth as much as the trigonometry, and the unit sits in the last line.

Science · 2 marks · CBSE 2024, paper 31/5/3, Q25

The linear magnification produced by a spherical mirror is + 3. Based on this statement answer the following questions : (a) What is the type of mirror ? (b) Where is the object located ? (c) List two properties of the image formed (other than the size/magnification).

The marking scheme

  1. (a) Concave mirror / Converging mirror½
  2. (b) Between pole and focus½
  3. (c) Any two: virtual, erect, behind the mirror½ + ½

Source: CBSE Marking Scheme 2024, Science (086), paper 31/5/3, Q25

Every part has its own mark, and part (c) is split again, one mark figure per property. A short answer to each part is all this question asks for.

Science · 2 marks · CBSE 2025, paper 31/1/3, Q26

Translate the following statements into chemical equations and then balance them : (a) Nitric acid reacts with calcium hydroxide to form calcium nitrate and water. (b) Sodium chloride reacts with silver nitrate to form silver chloride and sodium nitrate.

The marking scheme

  1. (a) 2HNO₃ + Ca(OH)₂ → Ca(NO₃)₂ + 2H₂O1
  2. (b) NaCl + AgNO₃ → AgCl + NaNO₃1

Source: CBSE Marking Scheme 2025, Science (086), paper 31/1/3, Q26

The scheme adds: Deduct half mark if equation is not balanced

One mark per equation, with a condition attached: right chemicals but unbalanced, and part of that mark goes.

Check your own answer

LazyTopper checks a written answer step by step: photograph or upload it and see the marks for every step and where marks were lost. The first check is free without an account.

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Quotations in “Marks are given for steps” are from the general instructions printed with the CBSE Marking Scheme 2024, Science (086), paper 31/5/3. LazyTopper is an independent platform and is not affiliated with CBSE.

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