IB DP Maths AI · Exam special · AA and AI · SL & HL · Paper 1 (AI), Paper 2, Paper 3 · ~13 min read
IB Maths GDC Guide: TI-84 Plus CE and Casio fx-CG50
The calculator skills IB examiners say students under-use, with menu paths for the TI-84 Plus CE and the Casio fx-CG50: solving, graphs, calculus, statistics, distributions, finance, tests, matrices and complex numbers.
Setup & angle modeSolverGraph: zero, max, min, intersectd/dx and ∫Tables & sequencesStatistics & regressionNormal, binomial, PoissonTVM finance
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No tag = SL and HLHL ONLY HL students onlyFORMULA BOOKLET given in the examM1A1 how marks are awardedhighlight = comes up again and againHANDY worth memorisingTest yourself at the end
In 30 seconds
- Every IB Maths subject report in 2024–25 said the same thing: students lose time and marks doing by hand what the GDC does in seconds. In AA Paper 2, "once an equation in one variable is obtained, the next mark is for the answer".
- But the GDC never replaces working. Write the equation you solved, the distribution with its parameters, or the TVM values, then the answer. A bare wrong answer scores nothing.
- Menu names below are for recent operating systems (TI-84 Plus CE OS 5.x, Casio fx-CG50 OS 3.x). Older versions put some items in a slightly different place; the function names are the same.
By the end you can
- Set up the GDC correctly before every paper.
- Solve equations, find intersections, derivatives and integrals in one step.
- Run statistics, distributions, hypothesis tests and finance calculations.
- Work with matrices and complex numbers (HL).
- Write the right working so method marks are safe.
1Before the exam
Setup and memory
| Task | TI-84 Plus CE | Casio fx-CG50 |
|---|---|---|
| Angle mode | MODE → RADIAN or DEGREE | SHIFT MENU (SET UP) → Angle → Deg or Rad |
| Show r and r² | MODE → STAT DIAGNOSTICS: ON | shown automatically |
| Store a value | STO→ then ALPHA letter (e.g. A) | → key then ALPHA letter |
| Use the last answer | 2nd (−) (Ans) | SHIFT (−) (Ans) |
| Exact fractions | MATH → ►Frac (or the n/d template) | F↔D key |
Exam tipAfter an exam reset, both calculators usually go back to radians. AI SL trig questions are in degrees; AA calculus is always in radians. Check the mode at the start of every trig or calculus question.
Common mistakeRetyping a rounded value. Store intermediate answers (STO→ A) and recall them. Premature rounding is the most common lost mark in every report.
2Solving equations
Solvers
| Task | TI-84 Plus CE | Casio fx-CG50 |
|---|---|---|
| One equation, one unknown | MATH → Solver (Numeric Solver): enter E1 and E2, then SOLVE | MENU → Equation → Solver: type the equation, SOLVE |
| Simultaneous linear equations | APPS → PlySmlt2 → Simultaneous Eqn Solver | MENU → Equation → Simultaneous → number of unknowns |
| Polynomial roots | APPS → PlySmlt2 → Polynomial Root Finder | MENU → Equation → Polynomial → degree |
| Roots, max, min | Y= then GRAPH; 2nd TRACE (CALC) → zero, minimum, maximum | MENU → Graph; DRAW; SHIFT F5 (G-SOLVE) → ROOT, MAX, MIN |
| Intersection of two graphs | 2nd TRACE (CALC) → intersect | G-SOLVE → INTSECT |
- Write: "x3 − 6x2 + 9x − 2 = 0 ⇒ x = 0.268, 2, 3.73" or "intersections of y = 2x and y = x + 3: x = −2.86 or x = 2.44". The equation is the method mark.
- Window: set it so every root and turning point you need is on screen. Examiners regularly see missed minima from a bad window.
Worked example
AA Paper 2: find a such that f′(1) = tan 70° when f′(1) depends on a.
- write the equation in a: f′(1) = tan 70° M1
- solve it with the solver or by graphing y = (your expression in a) and y = tan 70° M1
- read a, and check it is in the domain given A1R1
3Calculus on the GDC
Derivatives and integrals
| Task | TI-84 Plus CE | Casio fx-CG50 |
|---|---|---|
| Derivative at a point | MATH → nDeriv( (d/dx template), or 2nd TRACE → dy/dx on a graph | RUN-MATRIX → OPTN → CALC → d/dx |
| Graph a derivative (AI SL) | Y2 = nDeriv(Y1, X, X) | Y2 = d/dx(Y1, x) using OPTN → CALC |
| Definite integral | MATH → fnInt( (∫ template), or 2nd TRACE → ∫f(x)dx | OPTN → CALC → ∫dx, or G-SOLVE → ∫dx |
| Absolute value (areas, distance) | MATH → NUM → abs( | OPTN → NUMERIC → Abs |
| Sum of a sequence Σ | MATH → summation Σ( | OPTN → CALC → Σ( |
- Distance travelled = ∫ǀv(t)ǀ dt in one step: fnInt(abs(v), t, 0, 4). The May 2025 reports saw students split it into pieces and lose accuracy rounding each piece.
- Maximum speed: graph y = abs(v(x)) and use maximum.
- Find an unknown limit (AA median of a pdf, AA HL lower quartile): solve ∫am f(x) dx = 0.5 with the solver, using fnInt inside the equation.
Common mistakeDifferentiating by hand on Paper 2 when the question only needs a value. "Find the time when the acceleration is 5" can be done by graphing nDeriv(v) and intersecting with y = 5.
4Tables, sequences and recursion
Tables and recursion
| Task | TI-84 Plus CE | Casio fx-CG50 |
|---|---|---|
| Table of values | 2nd WINDOW (TBLSET), then 2nd GRAPH (TABLE) | MENU → Table |
| Recursive sequence | Home screen: type u₁, ENTER; then the rule using Ans, ENTER repeatedly | MENU → Recursion → aₙ₊₁ type, then TABLE |
| Euler's method (two variables) | Y+h(X+Y)→Y:X+h→X then ENTER repeatedly (use your own f(x, y)) | MENU → Spreadsheet: x in column A, y in column B, B2 = B1 + h × f(A1, B1), fill down |
- "First n for which…" (savings, populations, binomial n): make a table and write down the two values either side of the boundary as evidence. Example: for X ~ B(n, 0.08), P(X ≤ 6) = 0.3781 when n = 93 and 0.3667 when n = 94, so the largest n with P(X ≤ 6) > 0.37 is 93.
- Euler's method write-up (AA HL, AI HL): write the recursion with the question's variables, show the first step by hand, then the final value.
5Statistics and regression
Data, summaries and regression
| Task | TI-84 Plus CE | Casio fx-CG50 |
|---|---|---|
| Enter data | STAT → Edit → L1, L2 | MENU → Statistics → List 1, List 2 |
| Mean, σ, quartiles (frequency table) | STAT → CALC → 1-Var Stats, List: L1, FreqList: L2 | CALC → SET (1Var XList List1, 1Var Freq List2) → 1-VAR |
| Linear regression and r | STAT → CALC → LinReg(ax+b) L1, L2 | CALC → REG → X → ax+b |
| Other models | ExpReg, PwrReg, QuadReg, CubicReg, SinReg | REG → Exp, Pwr, X² (quad), X³ (cubic), Sin |
| Store the equation to graph it | LinReg… then Store RegEQ: Y1 | COPY (F5) after the regression |
- σₓ vs sₓ: σₓ is the population standard deviation (the one IB means by "standard deviation" in most questions); sₓ is the sample version. Read which one the question asks for.
- Spearman's rank: rank both variables (equal values get the mean rank), then run linear regression on the ranks: the r it gives is rs.
- Write: "y = 3.47x + 44.6, r = 0.996 (from GDC)" with both coefficients to 3 s.f.
6Probability distributions
Normal, binomial, Poisson
| Task | TI-84 Plus CE | Casio fx-CG50 |
|---|---|---|
| Normal P(a < X < b) | 2nd VARS (DISTR) → normalcdf(a, b, μ, σ) | STAT → DIST → NORM → Ncd |
| Inverse normal | DISTR → invNorm(area, μ, σ, LEFT/CENTER/RIGHT) | DIST → NORM → InvN, Tail: Left, Right or Central |
| Binomial P(X = r) | DISTR → binompdf(n, p, r) | DIST → BINOMIAL → Bpd |
| Binomial P(X ≤ r) | DISTR → binomcdf(n, p, r) | DIST → BINOMIAL → Bcd (set lower and upper) |
| Poisson (HL) | poissonpdf(m, r), poissoncdf(m, r) | DIST → POISSON → Ppd, Pcd |
- P(X ≥ 4) on a TI: 1 − binomcdf(n, p, 3). On the Casio, Bcd with lower 4 and upper n.
- Open-ended normal ranges: use −1E99 or 1E99 as the other bound.
- Unknown μ or σ: use invNorm on N(0, 1) to get z, then solve x − μσ = z (twice for two unknowns, with the simultaneous solver).
Common mistakeinvNorm(0.88) when 6% is in each tail. For P(a < X < b) = 0.88 symmetric about μ, the upper value has 0.94 to its left. Sketch first.
- Write: "X ~ B(20, 0.15), P(X ≤ 2) = 0.405" or "X ~ N(500, 12²), P(X < 480) = 0.0478". The distribution and the probability statement are the method mark.
7Finance (TVM solver)
TVM
| Task | TI-84 Plus CE | Casio fx-CG50 |
|---|---|---|
| Open the solver | APPS → Finance → TVM Solver | MENU → Financial → Compound Interest |
| Enter values | N, I%, PV, PMT, FV, P/Y, C/Y | n, I%, PV, PMT, FV, P/Y, C/Y |
| Solve for the unknown | move to it, ALPHA ENTER (SOLVE) | press the soft key for that variable (n, I%, PV, PMT or FV) |
| Balance after k payments | set N = k and solve for FV (or bal(k)) | set n = k and solve for FV (or AMORTIZATION) |
- Signs: money you receive is +, money you pay out is −. For a loan, PV > 0 and PMT < 0; for savings, PV < 0 or PMT < 0 and FV > 0.
- N is the total number of payments (years × payments per year). FV = 0 for a loan that is fully repaid.
- Write every value you entered: "N = 60, I% = 6, PV = 20 000, PMT = ?, FV = 0, P/Y = 12, C/Y = 12 ⇒ PMT = −386.66". Examiners award marks for the entries.
8Hypothesis tests and intervals
Tests
| Task | TI-84 Plus CE | Casio fx-CG50 |
|---|---|---|
| χ² test for independence | 2nd x⁻¹ (MATRIX) → EDIT A = observed; STAT → TESTS → χ²-Test | STAT → TEST → CHI → 2WAY, Observed: Mat A |
| Expected frequencies | stored in matrix B after the test | shown/stored as a matrix after the test |
| χ² goodness of fit | STAT → TESTS → χ²GOF-Test (observed L1, expected L2, df) | TEST → CHI → GOF |
| Two-sample t-test | STAT → TESTS → 2-SampTTest (Data; μ₁ > μ₂ etc.; Pooled: Yes) | TEST → t → 2-S, Pooled: On |
| Paired t-test (HL) | L3 = L1 − L2, then T-Test on L3 with μ₀ = 0 | List 3 = List 1 − List 2, then t → 1-S |
| Confidence interval (HL) | STAT → TESTS → TInterval or ZInterval | INTR → t or Z → 1-S |
- Write: the test, H₀ and H₁, the p-value (and χ² or t), the comparison with the significance level, and a conclusion in context. Templates are in AI write-up templates.
9Matrices (AI HL, AA HL systems)
Matrices
| Task | TI-84 Plus CE | Casio fx-CG50 |
|---|---|---|
| Enter a matrix | 2nd x⁻¹ (MATRIX) → EDIT | RUN-MATRIX → MAT/VCT (or the Matrix editor) |
| Inverse and solve AX = B | A⁻¹B | Mat A⁻¹ × Mat B |
| Powers (Markov, walks) | A^5 | Mat A ^ 5 |
| Determinant | MATRIX → MATH → det( | OPTN → MAT/VCT → Det |
| Eigenvalues | no direct key: solve det(A − λI) = 0 with the polynomial solver | no direct key: same method |
- Steady state (Markov): raise T to a high power (T^50) and read any column, or solve (T − I)s = 0 with the entries adding to 1.
10Complex numbers (AA HL, AI HL)
Complex mode
| Task | TI-84 Plus CE | Casio fx-CG50 |
|---|---|---|
| Complex mode | MODE → a+bi or re^(θi) | SET UP → Complex Mode → a+bi or r∠θ |
| Type i | 2nd . (i) | SHIFT 0 (i) |
| Modulus and argument | MATH → CMPLX → abs(, angle( | OPTN → COMPLEX → Abs, Arg |
| Convert form | MATH → CMPLX → ►Rect, ►Polar | OPTN → COMPLEX → ►a+bi, ►r∠θ |
- Phasors (AI HL): to add 14.8e1.27i + 18.5e−2.36i, type both in exponential form and convert the result. The May 2025 AI HL report said most students didn't do this step.
11What to write when you use the GDC
- Equations: write the equation before the solution.
- Distributions: name the distribution and its parameters, then the probability statement.
- Graphs: sketch with labelled axes, the window you used, and the key points with coordinates.
- Integrals and derivatives: write the integral with its limits, or "f′(2) = …".
- Finance: list every TVM entry.
- Tests: test name, hypotheses, p-value, comparison, conclusion in context.
- Never: "used GDC", a list of button presses, or a calculator screenshot copied as working.
Linking questionThe traps these skills prevent are listed in Maths AA exam traps and Maths AI exam traps.
Test yourself — cover the answers first
Quick check
- Which GDC tool finds where two graphs meet?
- For a loan, which values have opposite signs in the TVM solver?
- How do you find P(X ≥ 5) with binomcdf on a TI-84?
- What do you need to write besides the GDC answer for a normal probability?
- A reset GDC is usually in which angle mode?
Show answers
- intersect (G-SOLVE → INTSECT on Casio)
- PV and PMT
- 1 − binomcdf(n, p, 4)
- the distribution, its parameters and the probability statement
- radians
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