Most IB Maths calculator marks are lost on six tasks: normal distribution, binomial probabilities, intersections and turning points, definite integrals, polynomial equations, and statistics with regression. Each one now has a walkthrough on our calculator skills guides that lights up every key you press on the Casio fx-CG50 or TI-84 Plus CE, so you can follow along on your own calculator one press at a time.
How the walkthroughs work
Open a guide, choose your calculator's tab, and press Watch the key presses. You see a drawing of the calculator with each key lighting up as it is pressed, a strip of the keys so far, the screen after each press, and one line of explanation per step. You can pause, step back, step forward and change the speed. Nothing plays until you open it.
The key presses come from the same numbered steps as the written guide, and the answer at the end is the guide's worked example, so if your screen shows something different you know exactly which press to check. The TI-Nspire CX II has written steps on every guide but no walkthrough yet.
The six tasks
1. Normal distribution
On the fx-CG50: MENU, STATISTICS, F5 (DIST), F1 (NORM), then Ncd for a probability or InvN for a value. On the TI-84 Plus CE: 2nd, vars (DISTR), then normalcdf( or invNorm(.
The Casio asks for σ before μ; the TI asks for μ before σ. And $X \sim N(50, 64)$ means $\sigma = 8$, not 64. For inverse normal, $P(X > k) = 0.1$ means a left area of $0.9$. Normal distribution guide.
2. Binomial probabilities
fx-CG50: DIST, then F5 (BINOMIAL), Bpd for "exactly" and Bcd for a range, which takes a Lower and an Upper value. TI-84: binompdf( and binomcdf( in the DISTR list.
binomcdf always gives $P(X \leq x)$, so $P(X \geq 5)$ is $1 - P(X \leq 4)$, not $1 - P(X \leq 5)$. Write $X \sim B(12, 0.3)$ before the number: that line often carries the method mark. Binomial and Poisson guide.
3. Intersections, zeros, maximum and minimum
fx-CG50: draw both graphs, then SHIFT F5 (G-SOLVE) and F5 (INTSECT). TI-84: 2nd trace (CALC), 5: intersect.
If the turning point is off the screen, MAX finds an end point instead: widen the window first. Give both coordinates when the question says "coordinates", and never read answers off a trace, which only lands on pixel positions. Graphs guide.
4. Definite integrals
fx-CG50: RUN-MATRIX, OPTN, F4 (CALC), F4 (∫dx). TI-84: math, 9: fnInt(.
Check you are in radians: $\int_0^{\pi} \sin x \, dx$ should be $2$. If the curve dips below the $x$-axis, the integral subtracts that part, so for an area use the absolute value or split at the root. Derivatives and integrals guide.
5. Polynomial and simultaneous equations
fx-CG50: MENU, EQUATION, F2 (POLY). TI-84: apps, PlySmlt2, 1: Poly Root Finder or 2: Simult Eqn Solver.
$x^3 - 2x - 5 = 0$ has no $x^2$ term, so type its coefficient as $0$. Use the negative key (−), not subtract. Solving equations guide.
6. Statistics and regression
Enter $x$ in List 1 and $y$ in List 2, then run the regression; for a frequency table, set the frequency list. Clear old data and old frequency settings first.
Most questions want $\sigma_x$ (divide by $n$), not $s_x$. Know which letter is the gradient: in $ax + b$ form it is $a$. Quote $r$ only for a linear model. Regression guide and one- and two-variable statistics guide. AI students should also learn the finance (TVM) solver.
What to write down
A correct number from the GDC can earn full marks. A wrong number with no working earns nothing, because there is no method to credit. Write the probability statement, the equation you solved or the integral you found in normal notation, then the answer to 3 significant figures, keeping the full value for later parts. Calculator syntax such as normalcdf(45,60,50,8) is not working.
Exam-mode rules for IB exams
You may use a GDC on every AI paper and on AA Papers 2 and 3. AA Paper 1 has no calculator, so learn those methods by hand too. Exam mode goes on immediately before the exam and stays on, and CAS is not allowed.
- Casio fx-CG50: Examination Mode (for IB). Turn it off with SHIFT AC/ON, hold cos and 7, press AC/ON, then F1 (Yes). A green border shows it is on. Casio's UK Exam Mode has a magenta border and is not the IB one. Examination Mode turns off vector calculations, so practise vectors by hand.
- TI-84 Plus CE: do not use Press-to-Test: the IB says it blocks Apps such as PlySmlt2. Reset the RAM and the Archive Vars and remove non-approved Apps instead. Do not reset All Memory, which deletes PlySmlt2 as well.
- TI-Nspire CX II: Press-to-Test with the IB's settings, which your exams officer sets. The CAS model is allowed only with CAS disabled.
The IB updates its calculator rules each February, and your IB coordinator has the current copy. Step-by-step instructions are on the exam mode guide and the reset guide.
Practise with the walkthrough open
Pick one task a day. Watch the walkthrough once, then do the worked example on your own calculator without it, and check your answer against the guide.
Practise this topic
- How to do a normal distribution (normal cdf and inverse normal) on the Casio fx-CG50, TI-84 Plus CE and TI-Nspire CX II
- How to do binomial and Poisson probabilities (pdf and cdf) on the Casio fx-CG50, TI-84 Plus CE and TI-Nspire CX II
- How to find intersections, zeros, maximum and minimum points on the Casio fx-CG50, TI-84 Plus CE and TI-Nspire CX II
- How to find a numerical derivative and definite integral on the Casio fx-CG50, TI-84 Plus CE and TI-Nspire CX II
- How to solve equations, polynomials and simultaneous equations on the Casio fx-CG50, TI-84 Plus CE and TI-Nspire CX II
- How to do linear, exponential, power, polynomial, sine and logistic regression on the Casio fx-CG50, TI-84 Plus CE and TI-Nspire CX II
- How to put your calculator in exam mode (and exit it)
- Calculator skills for IB Maths
FAQ
Which IB Maths papers allow a calculator?
Every AI paper (SL Papers 1 and 2, HL Papers 1, 2 and 3), and AA Papers 2 and 3. AA Paper 1, SL and HL, is the paper with no technology.
Should I use Press-to-Test on the TI-84 Plus CE in IB exams?
No. The IB's 2026 calculator rules say not to use it, because it blocks Apps such as PlySmlt2. Reset the RAM and the Archive Vars and remove any non-approved Apps instead.
Which exam mode does the fx-CG50 need for IB exams?
Examination Mode (for IB), which puts a green border round the screen. Casio's UK Exam Mode, with a magenta border, is not the one for IB exams.
Every guide has the steps for the fx-CG50, TI-84 Plus CE and TI-Nspire CX II, a worked example to check your answer, and a key-by-key walkthrough.
Open the calculator skills guides →