IB Math RevisionWhere students lose marks — and exactly what to do about it
After every exam series the boards publish reports on where students lost marks. We read them, map every question to a topic, and turn the comments into a ranked checklist for your next exam. Our IB pages are based on the IB's own subject reports, which the IB releases to schools; each page lists exactly which reports it uses. They are our independent summaries, not IB publications.
Choose your course
Each page: the top mistakes with fixes and worked examples, a topic trend table, a per-paper view, and what to focus on next (clearly labelled as prediction).
IB Maths AA SL
IB Mathematics: analysis and approaches SL · 5 reports read
- Calculus in context: kinematics, integration with a boundary condition, optimisation
- Probability and distributions: conditional probability, binomial inequalities, normal bounds
- Functions: rational functions, transformations, inverses and logs
IB Maths AA HL
IB Mathematics: analysis and approaches HL · 2 reports read
- Calculus: volumes about the y-axis, differential equations, pdfs
- Proof, induction and complex numbers
- Trigonometric equations and vectors
IB Maths AI SL
IB Mathematics: applications and interpretation SL · 4 reports read
- Statistics: hypothesis tests, probability and distributions
- Finance, sequences and accuracy
- Calculus: tangents and normals, rates, trapezoidal rule, optimisation
IB Maths AI HL
IB Mathematics: applications and interpretation HL · 5 reports read
- Statistics: hypothesis tests and combined distributions
- Calculus: differential equations, volumes, rates in context
- Graph theory and vectors
The two mistakes that cost the most marks, course by course
The first two on each course page, ordered by how often and how widely they were reported, with the fix in one line. The course page has the worked examples and the rest of the list.
IB Maths AA SL
- Accuracy: 2 s.f. answers, early rounding and ignored accuracy instructions. Keep full calculator values (store them) until the very last line. Give final answers exactly or to 3 s.f. unless the question says otherwise, and when a given answer has more figures, show your value to more figures than that before rounding.
- "Show that": substituting or working back from the given answer. Start from the information in the question and write every step, left-hand side to right-hand side, until you reach the printed result, then say "as required". If you reject a value, give the reason in words.
IB Maths AA HL
- Accuracy: early rounding, 2 s.f. answers and ignoring the stated number of decimal places. Store full values and round once, at the end: exact or 3 s.f. unless told otherwise. When a question says "to 6 decimal places", do exactly that. For a given answer, show your value to more figures than the printed one.
- "Show that" and proofs: verifying, working backwards or working on both sides. Start from one side (or from the given facts) and move to the result line by line, with a reason for any condition such as a > 0. Give the reason for rejecting a solution in words. Never start from the printed answer.
IB Maths AI SL
- Accuracy: 2 s.f. answers, early rounding, and ignoring the accuracy asked for. Write the full calculator value, then round once: 3 s.f. unless the question says otherwise (keep trailing zeros). Read each question for its own rounding instruction and for context (whole years, whole items).
- No working shown: bare GDC answers and calculator notation. Write the formula or distribution first (X ~ B(n, p), P(X ≤ 3) = …), then the unrounded value, then the rounded answer. Convert calculator E-notation to a × 10ⁿ. Cross out the attempt you do not want marked.
IB Maths AI HL
- Accuracy: premature rounding, 2 s.f. answers and ignored instructions. Use the full GDC value in every later step, round once at the end to 3 s.f. (or as instructed), and write the unrounded value first. Round, don't truncate. Give a sensible level of accuracy for the context.
- Hypothesis tests: hypotheses in words, the wrong test, and conclusions that don't follow. Write H₀ and H₁ with symbols for population parameters (μ, ρ, p). Choose the test from the design (paired data → paired t; σ unknown → t). State the p-value, compare it with the stated significance level, then conclude in context. For goodness of fit: df = cells − 1 − parameters estimated.