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

1. First-time setup

Do this once, before every mock or real exam.

Turn on Exam Mode (required by IB regulations)

Hold MENU + 7 + + then power on with AC/ON. A green LED will flash for the duration of the exam. This wipes user memory and blocks unauthorised apps — invigilators must see the flashing light.

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. Where you'll spend 60% of your calculator time.

• Fractions: a b/c gives you nice mixed-number output. SHIFT F↔D toggles decimal ↔ exact fraction.
• Exact surds: SHIFT then ×10^x gives $\sqrt{\ }$ — the CG50 keeps $\sqrt 2$ etc. in exact form as long as your Answer Type in SETUP is set to "Real". Toggle with SHIFT F↔D.
• 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. Every AI & AA SL/HL Paper 2 will have a graph analysis question.

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). Used every single Paper 2.

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 → 8. Fastest way to solve any equation you can enter.

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

Graph Y1 then SHIFT F5 (G-Solv) → F6 (▷) → F1 (Y-CAL) then choose Y'. Enter the x-value.

Definite integral

Graph Y1 then SHIFT F5 (G-Solv) → F6 → F3 (∫dx). Enter lower and upper limits.

8. FINANCIAL (TVM) — compound interest & annuities

Menu → 4. AI SL/HL only — but appears every Paper 2.

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. Answer-type mode. If your fractions come out as decimals, toggle SHIFT F↔D. Marks are given for exact form when asked.
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. Not writing what you typed. IB Paper 2 gives method marks for showing the calculator command (e.g. "Ncd(20, 30, 4, 25) = 0.394"). If you only write the final number, you can lose 2 marks per question.