IB Maths exam tips: exam technique and top tips by topic

How IB Maths papers are marked and what earns the marks, then short pointers for each sub-topic with a worked mini-example. Free for students and teachers.

IB Maths exam technique: what earns the marks

Short answer: IB Maths papers are marked point by point. M marks reward a correct method, A marks a correct answer, R marks a reason in words, and AG means the answer is printed, so only your steps score. Good exam technique is showing those points on the page, to the right accuracy, at about a minute per mark.

Aiming for the top grade? How to get a 7 in IB Maths AA · How to get a 7 in IB Maths AI: the habits, where marks are lost and a plan to May 2027.

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The papers

Paper	Time	Marks	Calculator (GDC)
SL Paper 1	1 hour 30 minutes	80	AA: no technology allowed. AI: GDC allowed
SL Paper 2	1 hour 30 minutes	80	GDC allowed
HL Paper 1	2 hours	110	AA: no technology allowed. AI: GDC allowed
HL Paper 2	2 hours	110	GDC allowed
HL Paper 3	1 hour 15 minutes	Two extended problem-solving questions	GDC allowed

A clean copy of the formula booklet is given in every paper. Papers 1 and 2 work out at just over a minute per mark (90 minutes for 80 marks at SL, 120 for 110 at HL), so a 6-mark SL question is worth about 7 minutes. Dates for the next session: IB Maths exam dates.

Eight habits that earn marks

Write the method line first. The equation you solve, the integral you set up or the distribution you use usually carries the M mark, even if a slip follows.
Give reasons in words. "Since $f^{″} (1) < 0$ , it is a maximum": R marks need the reason, not just the verdict.
Answers exact or to 3 significant figures unless the question says otherwise, and keep full calculator values until the last line (see the example below).
Keep going after a slip. Follow-through (FT) lets you earn later marks with your own wrong answer, used correctly.
For "show that" (AG), show every step. The answer is printed, so the working is all that scores.
Read the command term. "Write down" needs little or no working; "hence" means use the part before. See IB Maths command terms.
Use your calculator well. On GDC papers, sketch and solve on the calculator and write down what you entered: calculator skills, key by key. On AA Paper 1, practise exact values by hand: AA SL Paper 1 tips.
Move on when stuck. If a question has taken twice as many minutes as it has marks, it is costing you easier marks later in the paper. Leave a gap, and come back to it at the end.

Worked example: where an accuracy mark goes

Question (Paper 2 style, 3 marks). In triangle ABC, AB = 7 cm, AC = 9 cm and angle BAC = 50°. Find the area of the triangle.

$Area = \frac{1}{2} \times 7 \times 9 \times \sin 50^{\circ}$ M1 A1 (the right formula with the right values)

$= 24.1304 \dots = 24.1 {cm}^{2}$ A1

How the A1 is lost: rounding $\sin 50^{\circ}$ to $0.77$ first gives $31.5 \times 0.77 = 24.255$ , so $24.3 {cm}^{2}$ : a perfect method, one mark gone. Keep the full value and round once, at the end.

The mark split is our own illustration in the IB style, not taken from an IB markscheme.

More on the codes, with a question marked line by line: how IB Maths is marked (M1, A1, R1) and how mark schemes work.

Put it into practice

Sit full papers under time: IB Maths past papers · prediction papers · HL: how to prepare for Paper 3 · how grades are set: IB Maths grade boundaries · what to revise: syllabus checklists and study guides.

Financial Mathematics

Simple interest is linear (same interest each year); compound interest grows exponentially.
Compounding period matters: for k periods per year at nominal rate r%, use $F V = P V (1 + r / (100 k))^{k n}$ .
Effective annual rate is what actually gets paid over one year: $(1 + r / (100 k))^{k} - 1$ , expressed as a %.

Q: €2000 at 6% p.a. compounded monthly for 5 years — value at end?

A: FV = 2000(1 + 0.06/12)⁶⁰ = 2000 × 1.005⁶⁰ ≈ €2697.70.

Q: Effective annual rate for 8% p.a. compounded quarterly?

A: (1.02)⁴ − 1 = 0.0824 → 8.24%.

Unit 3

Voronoi Diagrams

A Voronoi diagram partitions the plane so every point belongs to the region of its nearest 'site' (marked point).
The boundary between two adjacent regions is the perpendicular bisector of the segment joining those two sites.
Toxic waste dump problem: the optimal location is a vertex of the Voronoi diagram — the point *furthest* from all sites. Check every vertex; the answer is the one whose distance to its 3 nearest sites is largest.

Q: Given sites at (0,0), (6,0), (3,4) — which point is equidistant from all three (circumcentre)?

A: Circumcentre is the Voronoi vertex — solve the perpendicular-bisector equations pairwise. Here: (3, 7/8) ≈ (3, 0.875).

Unit 4

Chi-squared test

Use χ² for categorical data — testing whether observed frequencies match expected.
Test statistic: $χ^{2} = \sum \frac{(f_{o} - f_{e})^{2}}{f_{e}}$ . Degrees of freedom = (rows − 1) × (cols − 1) for contingency tables.
If your GDC gives p < significance level → reject H₀ (there is an association). If χ²_calc > χ²_crit → same conclusion.

Q: 2×3 table, χ²_calc = 8.2, 5% significance. Critical value χ²_crit(df=2, 0.05) = 5.99.

A: 8.2 > 5.99, so reject H₀ at the 5% level: there is significant association between the variables.

Unit 1

Approximation and error bounds

When determining upper and lower bounds for a calculated value, ensure you consider the maximum and minimum possible values for each input based on its stated precision. Think carefully about how these extremes combine in your calculations.
A common pitfall is forgetting the rules for setting bounds. If a value is given as $x$ to the nearest $0.1$ , its range is $[x - 0.05, x + 0.05]$ . If it's given to 2 significant figures, say $2.3$ , its range is $[2.25, 2.35]$ . Do not round intermediate calculations; only apply appropriate rounding for the final upper and lower bounds if specifically instructed.
Be mindful of how operations affect bounds. For addition, $LB (a + b) = LB (a) + LB (b)$ . For subtraction, $LB (a - b) = LB (a) - UB (b)$ . For multiplication (with positive values), $LB (a \times b) = LB (a) \times LB (b)$ . Similar rules apply for upper bounds and division.

Q: A rectangle has length $L = 8.5$ cm (1 d.p.) and width $W = 3.2$ cm (1 d.p.). Find the lower bound for its perimeter.

A: Lower bound for $L = 8.45$ cm. Lower bound for $W = 3.15$ cm. Perimeter LB $= 2 (LB (L) + LB (W)) = 2 (8.45 + 3.15) = 2 (11.60) = 23.20$ cm.

Unit 4

Linear regression on the GDC

Always ensure your GDC is set to the correct mode (e.g., 'Diagnostics On' for $r$ and $r^{2}$ ) and that all data points are entered accurately into lists. Even a single data entry error can lead to a completely incorrect regression equation and subsequent analysis.
A common pitfall is incorrectly identifying the independent (x) and dependent (y) variables in context. Swapping them will give an inverse relationship, drastically altering your regression equation and the meaning of any predictions.
When asked for the regression equation, ensure you state it in the exact form requested (e.g., $y = a x + b$ or $y = m x + c$ ) and use the original variable names from the problem (e.g., $C = a T + b$ if 'Cost' and 'Temperature' are given). Avoid premature rounding; use values from your GDC to at least 3 significant figures.

Q: The GDC output for a linear regression is $y = a x + b$ with $a = 0.7891$ and $b = 12.345$ . Write down the regression equation, rounding coefficients to 3 significant figures.

A: $y = 0.789 x + 12.3$ .

Q: For data showing a strong negative linear correlation, what would be a likely value for the correlation coefficient, $r$ ?

A: $r = - 0.91$ (or any value close to $- 1$ , e.g., $- 0.85$ to $- 0.99$ ).

Unit 1

Compound interest with sinking funds

Crucial Calculator Settings: Always verify your financial calculator (or GDC's TVM solver) has P/Y (payments per year) and C/Y (compounding periods per year) correctly set based on the question. A frequent error is defaulting both to 12 when they should be different (e.g., quarterly payments, monthly compounding).
Sinking Funds = Future Value: Sinking fund questions are fundamentally about accumulating a specific future lump sum through periodic payments. You will typically be solving for the payment (PMT) given a known Future Value (FV), rather than a Present Value (PV).
Identify All Variables: Before jumping into calculations, clearly list your N, I%, PV, PMT, FV, P/Y, and C/Y values. Ensure consistent signs for PV/PMT/FV; for a sinking fund, the FV is usually positive (target amount), and PMT will be negative (outflow).

Q: A company needs to accumulate \$500,000 in 4 years. What monthly payment must be made into a fund earning $5.4 %$ p.a. compounded monthly to reach this goal?

A: Using a TVM solver with $N = 4 \times 12 = 48$ , $I % = 5.4$ , $P V = 0$ , $F V = 500000$ , $P / Y = 12$ , $C / Y = 12$ , the required monthly payment is $P M T = - 9355.46$ , so \$9355.46 a month.

IB Maths exam tips: exam technique and top tips by topic

IB Maths exam technique: what earns the marks

The papers

Eight habits that earn marks

Worked example: where an accuracy mark goes

Put it into practice

Top tips by topic

Financial Mathematics

Voronoi Diagrams

Chi-squared test

Approximation and error bounds

Linear regression on the GDC

Compound interest with sinking funds

Top tips for every IB Maths course

SL AA tips

HL AI tips

HL AA tips

Practise the topics