How to make a table of values on the Casio fx-CG50
Fill in "complete the table" questions in seconds and spot sign changes for roots. Exact keystrokes for the fx-CG50 first, then the other calculators, a worked example you can check your answers against, the mistakes that cost marks, and the same thing in Desmos.
When you need it
Every "complete the table of values, then draw the graph of y = …" question. The table function fills it in exactly; then plot the points carefully.
Practise it: IGCSE units (Unit 3: Graphs).
Keystrokes on your calculator
Pick your calculator: the page remembers it next time.
Tables of values on the Casio fx-CG50
Written for OS 3.80 (menus unchanged from OS 3.60 onwards as far as we can tell). Casio fx-CG50: graphic (GDC).
- MENU 7 (TABLE).
- Type Y1 = X² − 3X + 1 and EXE.
- F5 (SET): Start −1 EXE, End 4 EXE, Step 0.5 EXE, then EXIT.
- F6 (TABLE). Scroll with ▼. Change any X value in the table to see y there.
- Two functions (Y1, Y2) give two columns: handy for comparing a model with data or for f(x) and g(x).
Tables of values on the TI-84 Plus CE
Written for OS 5.8.x. TI-84 Plus CE: graphic (GDC); also the TI-84 Plus CE Python / CE-T Python Edition.
- y=: Y1 = X² − 3X + 1.
- 2nd window (TBLSET): TblStart = −1, ΔTbl = 0.5, Indpnt: Auto.
- 2nd graph (TABLE). Scroll with the arrow keys.
- Set Indpnt: Ask to type in your own x values (useful for uneven tables).
Tables of values on the TI-Nspire CX II
Written for OS 6.x. TI-Nspire CX II: graphic (GDC), non-CAS; the CX II CAS is not allowed in IB, A Level or IGCSE exams.
- Graphs page: f1(x) = x² − 3x + 1.
- ctrl T shows the table next to the graph.
- menu → Table → Edit Table Settings: Table Start −1, Table Step 0.5.
Tables of values on the Casio fx-991EX ClassWiz
Written for the fixed ROM (these models take no OS updates). Casio fx-991EX ClassWiz: scientific (no graphs).
- MENU 9 (Table).
- Type f(x) = X² − 3X + 1, = (press = again to skip g(x)).
- Start −1 =, End 4 =, Step 0.5 =. The table appears.
- With both f(x) and g(x) the table holds up to 30 rows; with f(x) only, 45.
Tables of values on the Casio fx-991CW ClassWiz
Written for the fixed ROM (these models take no OS updates). Casio fx-991CW ClassWiz: scientific (no graphs); the newer ClassWiz with a HOME menu of apps.
- HOME → Table.
- Enter the function after f(x)=, then set Table Range: Start −1, End 4, Step 0.5.
- Choose Execute (or EXE) to show the table.
Worked example
Complete a table of y = x² − 3x + 1 for x = −1 to 4 in steps of 0.5, and find two intervals that contain a root.
Answers (checked with Python)
For example f(0) = 1, f(0.5) = −0.25, f(2.5) = −0.25, f(3) = 1. The sign changes between 0 and 0.5 and between 2.5 and 3, so there are roots in [0, 0.5] and [2.5, 3] (they are x ≈ 0.382 and 2.618).
Common calculator mistakes
- Squaring negatives: typing −1² gives −1. The table uses X² correctly, but when you check a value by hand, bracket it: (−1)².
- Step too large: a step of 1 can jump straight over two roots close together.
- A sign change shows a root only if the function is continuous there: y = 1/x changes sign at 0 with no root.
- Plot points from the table accurately and join them with a smooth curve, not straight lines.
Do it in Desmos
Not in the exam. Desmos is not allowed in IGCSE exams. Use it to learn, to check an answer and to see the graph behind a question.
- Define f(x) = x^2 − 3x + 1.
- Add a table (+ → table), put x₁ values −1, −0.5, … and f(x₁) as the second column heading: Desmos fills it in.
- The points appear on the graph; the curve shows where it crosses the axis.
Open desmos.com/calculator (free, in any browser) and type:
f(x)=x^{2}-3x+1table: x_1 = -1, -0.5, 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4; y_1 = f(x_1)
More calculator skills
Sources
- Casio fx-CG50 Software User's Guide, OS 3.70 (PDF) : Casio fx-CG50, OS 3.80 (menus unchanged from OS 3.60 onwards as far as we can tell).
- TI-84 Plus CE guidebook (Texas Instruments) : TI-84 Plus CE, OS 5.8.x.
- TI-Nspire CX II guidebooks (Texas Instruments) : TI-Nspire CX II, OS 6.x.
- Casio fx-991EX / fx-570EX Quick Start Guides : Casio fx-991EX ClassWiz, the fixed ROM (these models take no OS updates).
- Casio fx-991CW / fx-570CW User's Guide : Casio fx-991CW ClassWiz, the fixed ROM (these models take no OS updates).
- Desmos Help Center for the Desmos functions.
Menu names are taken from each manufacturer's manual for the OS versions shown. Menus can move slightly between OS updates: if a screen looks different on yours, the manual for your version is the reference, and please tell us so we can update this page. Worked-example answers were recomputed independently in Python.