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Where IB Mathematics Students Actually Lose Marks — And Why Knowing the Maths Isn't Enough
5 min readBy Renzo DiazLast reviewed October 7, 2026
In IB Mathematics, marks are lost less often for not knowing the mathematics than for not showing it in a form the examiner can award. Markschemes give separate marks for method, accuracy and reasoning, so a correct answer with no working may not earn full marks; numerical answers must be exact or correct to three significant figures unless the question says otherwise; and a final answer written in calculator notation is not accepted. In the exploration, 20% of the grade in both AA and AI, the criteria reward communication, personal engagement and reflection as well as correct mathematics.
A student can leave Paper 2 sure of every answer and still receive a lower grade than expected. The first reaction is to ask what went wrong. Often the more useful question is where the marks went, because knowing how to solve a problem is only part of what the papers reward.
This article sets out where marks go in IB Mathematics, Analysis and Approaches (AA) and Applications and Interpretation (AI) alike: how the papers award marks, the rules on accuracy and notation, the command terms, and the exploration. It draws on the IB's own documents, paraphrased: the two subject guides, the instructions printed on the May 2025 papers, and the instructions to examiners at the front of their markschemes.
The examiner can only award the evidence that appears in your work.
Key takeaways
- Working earns its own marks: method, accuracy and reasoning are marked separately, and accuracy marks usually depend on the method mark before them.
- Three significant figures: unless the question says otherwise, every numerical answer is exact or correct to 3 s.f.
- No calculator notation in a final answer: write 3.2 × 10⁻⁴, not 3.2E-4.
- Command terms set the evidence: "write down", "show that" and "hence" each ask for different working.
- The exploration rewards decisions: a correct but textbook-style exploration is unlikely to reach the higher levels of personal engagement.
How IB Maths papers award marks
The guides say that marks are awarded for method, accuracy, answers and reasoning, including interpretation. The papers repeat it above the first question: a correct answer with no working may not earn full marks, answers must be supported by working or explanation, and a solution found with a graphic display calculator (GDC) needs suitable working, such as a sketch of the graphs used. A wrong answer can still earn marks for a correct method, provided the method is written down.
The markscheme then labels each mark by what it rewards. Examiners are told not to award full marks automatically for a correct answer, and to check all the working.
| Mark | Awarded for | What it means for your working |
|---|---|---|
| M | An attempt to use a correct method | Show the method, not only its result |
| A | An answer, or accuracy; often dependent on the M mark before it | A right number after no visible method may not score |
| R | Clear reasoning | Say why a step holds, not only what it gives |
| AG | Nothing: the answer is given in the question | In a "show that", every mark is for the route |
| FT | Correct work that uses an earlier wrong result | Usually needs the working to be present |
Source: the instructions to examiners in the IB markschemes for Mathematics: analysis and approaches HL Paper 2 and applications and interpretation SL Paper 1, May 2025, paraphrased. Checked 7 October 2026.
Marking rules worth knowing
What happens to extra and crossed-out work
Once a correct answer is seen, later working is generally ignored, even if it is wrong; the exception is a wrong decimal approximation that is then used in a later part, which costs the final mark of the first part. Crossed-out work is not marked unless the student asks for it to be, and when two different answers are offered, only the first is marked.
Accuracy, exact values and calculator notation
The rule printed on the front of the IB Mathematics papers is short: unless the question says otherwise, numerical answers are given exactly or correct to three significant figures. When a question does specify the accuracy, a mark is linked to it. An exact answer such as √7 is not the same as its decimal: if the question asks for an exact value, 2.65 does not answer it.
Rounding early is the quieter risk. The markscheme usually works with exact values and accepts three-significant-figure values carried into later parts, but a value rounded harder than that drifts through a calculation chain. Keep full precision in the calculator and round only the answer you report.
The calculator rule is stricter than many students expect. Both guides state that students must use correct mathematical notation, not calculator notation, and the markschemes do not accept a final answer written in calculator notation, though method marks and intermediate accuracy marks can still be earned from it. A bare number also says less than an answer tied to the question: "the predicted speed is 14.7 m s⁻¹" says what "14.7" leaves out, especially in AI, where the mathematics serves a context.
| Rule | Applies to | Example | Source |
|---|---|---|---|
| Numerical answers exact or correct to 3 significant figures, unless the question says otherwise | AA and AI papers | √7, or 2.65; not 2.6 | Instructions to candidates on the May 2025 papers; markscheme instructions |
| No calculator notation in a final answer | AA and AI papers | 3.2 × 10⁻⁴, not 3.2E-4 | Notation list in both guides; markscheme instructions |
| Angles in radians unless the question says otherwise | AA at SL and HL; AI HL | An angle of 0.524, not 30 | AA guide, p. 44; AI guide, p. 45 |
| Radians are not required | AI SL | Angles in degrees | AI guide, p. 44 |
Sources: IB Mathematics: analysis and approaches guide and applications and interpretation guide (first assessment 2021); instructions to candidates and to examiners for the May 2025 papers (AA HL Paper 2, AI SL Paper 1). Paraphrased; checked 7 October 2026.
Calculator mode errors
In AA, and on AI HL papers, radian measure is assumed unless the question indicates otherwise; AI SL does not require radians at all. A calculator left in the wrong mode produces a plausible number that is wrong, and no amount of sound reasoning recovers the answer marks. Check the mode at the start of every calculator paper, and again after any question that asked for degrees.
Command terms decide what evidence to give
IB Mathematics uses a glossary of command terms, printed in both guides, and they are not interchangeable ways of saying "do the question". The term tells you what evidence the examiner expects, so read it, and mark it, before touching the mathematics.
| Command term | Meaning in the guide, paraphrased | What it asks of your working |
|---|---|---|
| Write down | Obtain the answer, usually by reading it off; little or no calculation | No working needed |
| Find | Obtain an answer, showing the relevant stages of the working | The stages, not only the result |
| Determine | Obtain the only possible answer | One answer, reached by working that leads to it |
| Show that | Obtain the given result without the formality of proof; generally needs no calculator | A route that ends at the result, never one that starts from it |
| Prove | Reach the result by a sequence of logical steps, formally | A complete argument |
| Verify | Give evidence that validates the result | A check, for example by substitution |
| Justify | Give valid reasons or evidence for an answer or conclusion | Reasons, not only the value |
| Hence | Use the preceding work to obtain the result | Another method earns no credit unless the markscheme allows it |
| Hence or otherwise | The preceding work is suggested, but other methods can earn credit | Any valid method |
Sources: glossary of command terms in the IB Mathematics: analysis and approaches guide, pp. 89–90, and the applications and interpretation guide, which gives the same definitions; the rules for "hence" from the May 2025 markschemes. Paraphrased; checked 7 October 2026.
Why working backwards fails a show-that question
A "show that" question gives you the target. Substituting the given answer into an earlier formula and finding that it fits is verification, not the derivation the question asks for. The markscheme marks the given answer as AG, worth nothing in itself, so every mark sits in the route that leads to it.
Warning
If you cannot finish a show-that, use the given result
When a later part depends on a "show that", use the value the question gave you, not the one your unfinished working produced. The markscheme gives no follow-through marks for later work built on an answer that contradicts the given one.
Where the exploration loses marks
The mathematical exploration is 20% of the final grade in AA and in AI, at SL and HL. It is a written report on a topic the student chooses, marked out of 20 on five criteria: presentation, mathematical communication, personal engagement, reflection and use of mathematics. The marks for each, and the four criteria that replace them for students first examined in May 2029, are set out in IB Maths IA criteria by exam year.
A student who does well in timed papers can still score poorly here, because the criteria reward things the papers do not. The guide's own notes make the point: personal engagement is not a measure of effort, and an exploration in textbook style, reproducing mathematics that is readily available without the student's own perspective, is unlikely to reach its higher levels. Simply describing results counts as limited reflection. And obtaining a correct answer is not enough to demonstrate understanding under use of mathematics.
Notation in the exploration
Calculator notation counts against communication
Under mathematical communication, calculator and computer notation is acceptable only when it is software-generated, such as a printed spreadsheet. Anything the student types should be in proper mathematical notation, with key terms and variables defined.
A correct exploration can still be a weak one
Imagine two explorations of population growth, both with correct mathematics and clean graphs. One reproduces a standard model as it appears in textbooks. The other defines a specific question, states its assumptions, explains why the model suits the data, examines where it fails and refines the approach when the results disagree with expectations. They have not demonstrated the same thing, and the criteria are written to tell them apart.
The useful question about an exploration is therefore not only "is the mathematics correct?" but "can the reader see why I made each decision?" Why this model, this dataset, this assumption; why an earlier approach was dropped. Those reasons are the evidence of engagement and reflection the criteria look for.
Can the examiner see my mathematical decision-making?
How to review a past paper for evidence, not answers
Checking a past paper only against the final answers tests one part of what the exam rewards. The other part, the working, the notation and the command terms, needs its own review.
Five questions for each answer
What did the command term ask for?
Compare what you wrote with the meaning of the term: a "show that" needs a complete route, a "hence" needs the previous part.
Would the method marks stand without the final number?
Cover the answer and read the working. If the method is not visible, the M marks are not there either.
Did the calculator work leave evidence?
Write what was calculated and how: the equation solved, the graph sketched, the values entered.
Is the answer in the required form?
Exact where asked, otherwise three significant figures, in mathematical notation, with units where the context has them.
Name the evidence that was missing
For each lost mark, write what the examiner needed to see. That list, not the score, is the revision plan.
You do not receive marks for what you know but fail to demonstrate.
Terms used in this article
- Markscheme
- The IB's instructions to examiners on how the marks for each question are awarded, opening with general rules for the whole paper.
- M, A and R marks
- Marks for an attempt at a correct method (M), for an answer or its accuracy (A, often dependent on the M mark before it) and for clear reasoning (R).
- AG
- "Answer given": the result printed in a "show that" question, which earns no marks by itself.
- Follow through (FT)
- Marks awarded for correct work that uses an earlier wrong result, usually only when the working is shown.
- Command term
- A word such as "find", "show that" or "hence" whose meaning the IB defines in each subject guide, telling the student what kind of answer is required.
- Exploration
- The internal assessment of IB Mathematics: a written report on a topic the student chooses, marked by the teacher and moderated by the IB, worth 20% of the grade.
Questions about losing marks in IB Maths
Do you lose marks for not showing working in IB Maths?
You can. A correct answer with no working may not earn full marks, because the markscheme gives separate marks for method and reasoning; with a wrong answer, written working is the only way to earn method marks.
How many significant figures should IB Maths answers have?
Three, unless the question says otherwise, or the exact value. The rule is printed on the front of the papers, and when a question sets its own accuracy, a mark is linked to it.
Should my calculator be in degrees or radians for IB Maths?
Radians, unless the question says otherwise, in AA and on AI HL papers. AI SL does not use radians, so its angles are in degrees.
Can I write calculator notation like 3.2E-4 in an IB Maths exam?
Not in a final answer. The markschemes do not accept final answers in calculator notation; write 3.2 × 10⁻⁴. Method marks can still be earned from intermediate work.
What does "hence" mean in an IB Maths question?
Use your answer to the previous part to get the result. With "hence" alone, another method usually earns no credit; "hence or otherwise" allows any valid method.
What is the difference between "show that" and "prove" in IB Maths?
"Show that" asks you to reach a given result; "prove" asks for a formal sequence of logical steps. In both, the marks are for the route, not for the result printed in the question.
Written by
Teaching IB since 2016. Seven years of IB reviews you can check on Google — and named results with the documents behind them.
Last reviewed October 7, 2026
Sources
The rules here come from the IB's own documents: the Mathematics: analysis and approaches and applications and interpretation guides (first assessment 2021), and the instructions to candidates and to examiners printed on the May 2025 papers and their markschemes. Page numbers refer to the guides' edition published February 2019. The guides are made available to schools, and the papers and markschemes are sold; all are paraphrased here, not reproduced. The advice on reviewing a past paper is teaching practice. Checked on 7 October 2026.
- IB Organisation — Mathematics in the DP (the two courses and their assessment)
- IB Organisation — Mathematics: analysis and approaches updates (the revised exploration, first assessment May 2029)
- IB Organisation — Mathematics: analysis and approaches guide (first assessment 2021)
- IB Organisation — Mathematics: applications and interpretation guide (first assessment 2021)