The six calculator tasks that come up again and again in A Level and International A Level Maths are normal distribution, binomial probabilities, definite integrals, polynomial and simultaneous equations, tables of values for change of sign, and summary statistics. Each now has a walkthrough on our calculator skills guides that lights up every key you press on the Casio fx-991EX, Casio fx-CG50 or TI-84 Plus CE.
How the walkthroughs work
Open a guide, choose your calculator's tab, and press Watch the key presses. A drawing of the calculator lights each key as it is pressed, with the screen after each press and one line of explanation per step. Pause, step back, step forward or slow it down; nothing plays until you open it.
The key presses follow the guide's own numbered steps, and the final screen shows the guide's worked-example answer, so you can check your calculator against it press by press. The fx-991CW and TI-Nspire CX II have written steps but no walkthrough yet.
The six tasks
1. Normal distribution
fx-991EX: MENU 7 (Distribution), then Normal CD for a probability or Inverse Normal for a value. On the fx-CG50 it is STATISTICS, F5 (DIST), F1 (NORM); on the TI-84, 2nd vars (DISTR).
The Casio calculators ask for σ before μ, the TI for μ before σ. $N(50, 64)$ means $\sigma = 8$. The fx-991EX's Inverse Normal always uses the area to the left, so $P(X > k) = 0.1$ needs an area of $0.9$. On IAL S1, write the standardising line as well: it carries the method mark. Normal distribution guide.
2. Binomial probabilities
fx-991EX: MENU 7, then Binomial PD (exactly) or Binomial CD (at most), and choose Variable.
$P(X \geq 5)$ is $1 - P(X \leq 4)$. Type $p$ as $0.3$, not $30$. State the distribution, $X \sim B(12, 0.3)$, before the answer. The same menu has Poisson PD and CD. Binomial and Poisson guide.
3. Definite integrals
fx-991EX: in Calculate, press the integral key, type the function, then the limits. fx-CG50: RUN-MATRIX, OPTN, F4 (CALC), F4 (∫dx). TI-84: math, 9: fnInt(.
Use it to check a definite integral, not to replace it: "use calculus" and "show that" questions need the working, and a calculator value alone scores little. Trig integrands need radians. Derivatives and integrals guide; the trapezium rule guide covers the estimate questions.
4. Polynomial and simultaneous equations
fx-991EX: MENU, Equation/Func, then Polynomial and the degree. fx-CG50: EQUATION, F2 (POLY). TI-84: apps, PlySmlt2.
Type $0$ for a missing term: $x^3 - 2x - 5$ is $1, 0, -2, -5$. Use the negative key, not subtract. After the factor theorem, this is a fast way to check all three roots. Solving equations guide.
5. Tables of values and change of sign
The table function gives $f(x)$ at regular steps, which is how you spot a root before a change-of-sign argument or an iteration.
A step that is too large can jump over two roots close together, and a sign change proves a root only if $f$ is continuous there: $y = \frac{1}{x}$ changes sign at $0$ with no root. Write the conclusion sentence. Tables of values guide.
6. Statistics and regression
fx-991EX: MENU 6 (Statistics). For a frequency table, turn the Freq column on first in SETUP. OPTN then gives the 1-Variable or Regression results.
Know whether the question wants $\sigma_x$ or $s_x$. On the fx-991EX the model is $y = a + bx$, so the gradient is $b$; on the fx-CG50's $ax + b$ it is $a$. Statistics guide and regression guide.
Exam-mode rules for A Level
Every A Level and IAL Maths paper allows a calculator. Under the JCQ rules it must not do symbolic algebra, symbolic differentiation or integration, or communicate with other machines or the internet, and it must not hold stored information such as formulae or text. JCQ's 2026–27 instructions accept a calculator's exam mode when it is switched on and makes the calculator compliant, and add that the candidate must ensure their calculator is in exam mode.
- Casio fx-991EX: no exam mode. If your exams officer asks for a reset: SHIFT 9 (RESET), Initialize All, Yes.
- Casio fx-CG50: Casio's UK Exam Mode: hold U and K and press AC/ON; a magenta border shows it is on. Ask your exams officer whether they want exam mode or a reset.
- TI-84 Plus CE: Press-to-Test. With the calculator off, hold ◄, ► and on, choose the options and OK. The status bar turns blue and shows TEST MODE ENABLED.
The TMUA is different: no calculator at all. Full steps are on the exam mode guide and the which calculators are allowed guide.
One task a day
Watch a walkthrough once, then do the worked example on your own calculator with the walkthrough closed, and check your answer against the guide.
Practise this topic
- How to do a normal distribution (normal cdf and inverse normal) on a Casio ClassWiz or fx-CG50
- How to do binomial and Poisson probabilities (pdf and cdf) on a Casio ClassWiz or fx-CG50
- How to find a numerical derivative and definite integral on a Casio ClassWiz or fx-CG50
- How to solve equations, polynomials and simultaneous equations on a Casio ClassWiz or fx-CG50
- How to make a table of values on a Casio ClassWiz or fx-CG50
- How to find the mean, standard deviation and quartiles (1-var and 2-var statistics) on a Casio ClassWiz or fx-CG50
- How to put your calculator in exam mode (and exit it)
- Calculator guide for A Level Maths
FAQ
Is a calculator allowed in every A Level Maths paper?
Yes. UK A Level (Edexcel, AQA, OCR) and Edexcel International A Level allow a calculator in every paper, IAL P1 included. It must not do symbolic algebra, symbolic differentiation or integration, or communicate with other devices.
Does the fx-991EX have an exam mode?
No. It is a scientific calculator with no CAS and no wireless link. If your exams officer asks for a reset, use SHIFT 9 (RESET), Initialize All, Yes.
Is a calculator allowed in the TMUA?
No. UAT-UK says calculators are not permitted in either the ESAT or the TMUA.
Every guide has the steps for the Casio fx-991EX, fx-991CW, fx-CG50, TI-84 Plus CE and TI-Nspire CX II, with a worked example to check your answer.
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