Casio fx-CG50 — Every Menu You'll Actually Use

1. First-time setup

Do this once, before every mock or real exam.

Turn on Examination Mode (for IB)

Turn the calculator off (SHIFT AC/ON). Hold cos + 7 and press AC/ON, then F1 (Yes), F2 and EXIT. A green border round the screen shows Examination Mode (for IB). The IB says it goes on immediately before the exam and stays on for the whole exam. It ends by itself after 12 hours, or when you link the calculator by 3-pin cable to one that is not in Exam Mode. It blocks stored programs and data while it is on; your school may set it for you on the day.

Not the UK Exam Mode. Casio UK warns that its UK Exam Mode (hold U and K and press AC/ON; magenta border) is not allowed in IB exams. Sources: Casio Education FAQ, Casio UK: preparing students using the fx-CG50 in exams, and the IB's Use of calculators in IB DP examinations 2026 (sent to schools). Exam mode step by step.

Set angle to radians (AA) or match your paper

Press SHIFT MENU (SET UP) → scroll to Angle → choose Rad for AA (all trig integrals, calc etc. are in radians). AI Paper 2 depends on the question — read the prompt.

2. RUN-MAT — the workhorse

Menu → 1. Most everyday calculating happens here.

• Fractions and surds: in Math input/output mode (SET UP), simple results such as $\frac{3}{4}$ and $\sqrt{2}$ are shown exactly, and the fraction–decimal key switches between the exact and the decimal form. $\sqrt{}$ is SHIFT x².
• Derivative at a point: OPTN F4 (CALC) F2 (d/dx), type the function, then the $x$-value.
• Store values: → then a letter (A-Z) stores. Saves rewriting long constants.
• Ans key: SHIFT (-) pastes the previous answer. Critical for multi-step questions.

3. GRAPH — plotting & analytical shortcuts

Menu → 5. Graph questions (roots, intersections, maximum and minimum) come up on most calculator papers.

Plot a function

Enter your function in Y1, press EXE, then F6 (DRAW). If your graph looks tiny/empty, press SHIFT F3 (V-Window) — set Xmin/Xmax/Ymin/Ymax to something sensible (default is often too zoomed-out).

Find a root (x-intercept)

With the graph showing: SHIFT F5 (G-Solv) → F1 (ROOT). Arrow-left/right to move between roots.

Find intersection of two curves

Plot Y1 and Y2, DRAW, then SHIFT F5 (G-Solv) → F5 (INTSECT). Pick each curve when prompted.

Find max / min of a curve

SHIFT F5 → F2 (MAX) or F3 (MIN). The CG50 gives you both $x$ and $y$ — write both on your paper.

4. STATISTICS — 1-var, box plots, correlation, regression

Menu → 2. Heavy for AI (both papers) and AA Paper 2.

Enter data

List1 for single-variable data; List1 & List2 for bivariate (correlation, regression).

1-variable summary (mean, median, quartiles, standard deviation)

F2 (CALC) → F6 (SET) → confirm 1Var XList: List1, Freq: 1. Then F2 (CALC) → F1 (1-VAR). Scroll down for Q1, Q3, and the sample vs. population SD.

Box plot

From STAT list: F1 (GRAPH) → F6 (SET) → choose MedBox. Then F1 to draw. Use SHIFT F1 (TRACE) to read Q1, median, Q3.

Linear regression & r

Data in List1 (x) and List2 (y). F2 (CALC) → F3 (REG) → F1 (X). Gives you $a$, $b$, $r$, and $r^2$. To plot the line on top of a scatter: F6 (DRAW) after regression.

5. DISTRIBUTION — the AI/AA statistics essential

Menu → 2 (STAT) → F5 (DIST). Normal and binomial questions come up on most calculator papers.

Normal probability (find P(a < X < b) )

DIST → F1 (NORM) → F2 (Ncd). Enter Lower, Upper, σ, μ. Output is the probability.

Inverse normal (find x such that P(X<x) = p)

DIST → NORM → F3 (InvN). Set Tail = "Left", enter Area = p, σ, μ. Output is x.

Binomial P(X = r) and P(X ≤ r)

DIST → F5 (BINM) → F1 (Bpd) for exactly r, or F2 (Bcd) for cumulative. Enter x-value, Numtrial (n), and p.

6. EQUATION — simultaneous, polynomial, general solver

MENU, then EQUATION (the icon labelled A). The fastest way to solve an equation you can type in.

Simultaneous linear

F1 (SIMUL) → choose 2, 3 or 4 unknowns → enter the coefficient matrix and constants → F1 (SOLV).

Polynomial (up to degree 6)

F2 (POLY) → degree → coefficients → SOLV. Complex roots appear if the polynomial has them (useful for AA HL complex numbers).

General solver

F3 (SOLVER). Type the equation with an "=" (e.g. $x^3-2x+1=0$), pick the variable, tap F6 (SOLV). Provide a start estimate close to the expected root.

7. Numerical calculus — dY/dx and ∫f dx from GRAPH

The CG50 will numerically differentiate and integrate any Y1 you graph.

Value of the derivative at a point

In RUN-MATRIX: OPTN F4 (CALC) F2 (d/dx). Type the function, move to the box after $x=$, type the $x$-value and press EXE.

Definite integral

In RUN-MATRIX: OPTN F4 (CALC) F4 (∫dx), then the function and the two limits. Or graph Y1, then SHIFT F5 (G-Solv) → F6 (▷) → ∫dx and pick the lower and upper limits: the region is shaded and its value shown. Step-by-step with screens: numerical derivative and integral on the fx-CG50.

8. FINANCIAL (TVM) — compound interest & annuities

MENU, then FINANCIAL (highlight it and press EXE). AI SL and HL only.

The TVM Solver is the shortcut. Fields: n (number of periods), I% (interest per year), PV (present value — enter as negative when investing), PMT (regular payment), FV (future value), P/Y (payments per year), C/Y (compounding periods per year). Put a placeholder in the unknown and press F6 (SOLV).

9. Six traps that cost marks

1. Deg vs. Rad. Every AA calc question is Rad. Set it once, before you start.
2. Exact or decimal. If your fractions come out as decimals, press the fraction–decimal key. When a question asks for an exact answer, a decimal does not earn the mark.
3. V-Window too zoomed. Roots and intersections that "don't exist" are usually outside your viewing window. Reset to SHIFT F3 → F1 (INIT).
4. Rounding too early. Store intermediate values in variables (A-Z) — never re-type 3.14159 back in. The CG50 preserves 15 significant figures internally; use them.
5. 1-VAR SD choice. The exam wants x-σn (population) unless it explicitly asks about a sample.
6. Writing calculator syntax as working. Write the maths: for $X\sim N(25,4^2)$, write $P(20<X<30)=0.789$, not "Ncd(20, 30, 4, 25)". A bare number with no statement risks the method marks if it is wrong.