Try the new site navigation Optional. The classic menu stays available.
Casio Calculator Skills – fx-83GT CW | Maths Vault
← GCSE revision tools

Casio calculator skills

Button sequences for common GCSE calculator paper tasks, plus the extra fx-991CW tools used at A-level. The fx-83GT CW uses HOME and SETTINGS (the same presses work on the fx-85GT CW). The green screens under each skill show what the display looks like. Always check your exam board allows your model.

Casio fx-83GT CW

The ClassWiz with HOME and SETTINGS. The same key presses apply to the fx-85GT CW.

Buy on Amazon
Casio fx-83GT X

The earlier fx-83/85 GT. Use the MODE column if your calculator has a MODE key.

Buy on Amazon
Casio fx-991CW

Advanced ClassWiz for GCSE and A-level. Adds equations, distribution, vectors and calculus. The fx-991CW+ uses the same presses.

Buy on Amazon

As an Amazon Associate, Maths Vault earns from qualifying purchases.

Standard form

Type 3.2×10⁷
Ordinary display
Number format
Sci, 3 figures

fx-83GT CW

  1. Press HOME, choose Calculate, then OK.
  2. To type 3.2×10^7: press 3.2, then ×10^x, then 7, then EXE.
  3. To show answers in standard form: SETTINGS → Calc Settings → Number Format → Sci. Choose how many significant figures (for example 3), then OK. Press AC to get back to the calculation.
  4. Sci rounds the display. For a normal display again: SETTINGS → Calc Settings → Number Format → Norm → Norm 2.

fx-83/85 GT (MODE)

  1. Press MODE → 8: Norm → 1: Sci
  2. Enter mantissa, press EXP or ×10^, enter power
  3. Example: 3.2×10^7 → 3.2 EXP 7

fx-991CW

  1. Press HOME, choose Calculate, then OK.
  2. To type 3.2×10^7: press 3.2, then ×10^x, then 7, then EXE.
  3. To show answers in standard form: SETTINGS → Calc Settings → Number Format → Sci. Choose how many significant figures (for example 3), then OK. Press AC to get back to the calculation.
  4. Sci rounds the display. For a normal display again: SETTINGS → Calc Settings → Number Format → Norm → Norm 2.

Table of values (y =)

Open Table
Define f(x)
The table

fx-83GT CW

  1. Press HOME, choose Table, then OK.
  2. Press TOOLS → Define f(x)/g(x) → Define f(x). Type the rule, for example 2x+3, using the x key. Press EXE.
  3. Press TOOLS → Table Range. Enter Start, End and Step, then EXE.
  4. Scroll the table with the arrow keys. Leave g(x) empty if you only need one function.

fx-83/85 GT (MODE)

  1. Press MODE → 3: Table
  2. Enter function e.g. 2X+3
  3. Set Start, End, Step — press AC/C to view table

fx-991CW

  1. Press HOME, choose Table, then OK.
  2. Press TOOLS → Define f(x)/g(x) → Define f(x). Type the rule, for example 2x+3, using the x key. Press EXE.
  3. Press TOOLS → Table Range. Enter Start, End and Step, then EXE.
  4. Scroll the table with the arrow keys. Leave g(x) empty if you only need one function.

Solve equation

No Equation app
x²−4 = 0 in Table
Open Equation
Quadratic coefficients
The two roots

fx-83GT CW

  1. The fx-83GT CW has no equation mode, so there is no EQN app.
  2. Check a value in Calculate, or use Table and read the row where f(x) = 0.
  3. For a written method, use the simultaneous equations solver on Maths Vault.

fx-83/85 GT (MODE)

  1. Press MODE → 5: EQN
  2. Choose polynomial degree or simultaneous
  3. Enter coefficients as prompted

fx-991CW

  1. Press HOME, choose Equation, then OK. Choose Polynomial, then the degree (2 for a quadratic).
  2. For x² − 5x + 6 = 0, enter a = 1, b = −5, c = 6, then EXE.
  3. The screen shows x₁ = 2 and x₂ = 3. Use the down arrow if a root is off the screen.
  4. On an fx-991EX, open Equation from MENU instead of HOME.

Statistics — single list

1-Variable list
1-Var Results

fx-83GT CW

  1. Press HOME, choose Statistics, then OK. Choose 1-Variable, then OK.
  2. Type each value and press EXE. To wipe the list: TOOLS → Edit → Delete All.
  3. For a frequency column: TOOLS → Frequency → On, then fill Freq.
  4. Press OK, choose 1-Var Results, then OK. The mean is x̄. σx is the population standard deviation and sx is the sample standard deviation.

fx-83/85 GT (MODE)

  1. Press MODE → 2: Stat → 1: 1-VAR
  2. Shift STAT → Del to clear if needed
  3. Enter data values, AC/C to finish
  4. Shift STAT → 4: Var to find mean, σ, etc.

fx-991CW

  1. Press HOME, choose Statistics, then OK. Choose 1-Variable, then OK.
  2. Type each value and press EXE. To wipe the list: TOOLS → Edit → Delete All.
  3. For a frequency column: TOOLS → Frequency → On, then fill Freq.
  4. Press OK, choose 1-Var Results, then OK. The mean is x̄. σx is the population standard deviation and sx is the sample standard deviation.

Fractions

1/2 + 1/4
Fraction answer
FORMAT menu
Decimal answer

fx-83GT CW

  1. In Calculate, press the fraction key (a box over a box) and fill the numerator and denominator, then EXE.
  2. For a mixed number, press SHIFT then the fraction key.
  3. Press FORMAT. Choose Decimal for a decimal, or Standard for a fraction. If the answer changes straight away, press FORMAT again to switch back.
  4. For mixed or improper answers: SETTINGS → Calc Settings → Fraction Result → Mixed Fraction or Improper Fraction.

fx-83/85 GT (MODE)

  1. Press a b/c key for mixed numbers
  2. Use S↔D to switch between fraction and decimal answers

fx-991CW

  1. In Calculate, press the fraction key (a box over a box) and fill the numerator and denominator, then EXE.
  2. For a mixed number, press SHIFT then the fraction key.
  3. Press FORMAT. Choose Decimal for a decimal, or Standard for a fraction. If the answer changes straight away, press FORMAT again to switch back.
  4. For mixed or improper answers: SETTINGS → Calc Settings → Fraction Result → Mixed Fraction or Improper Fraction.

Trigonometry

Degrees is on
Exact value

fx-83GT CW

  1. A small D at the top of the screen means degrees. R means radians.
  2. If you need degrees: SETTINGS → Calc Settings → Angle Unit → Degree, then OK, then AC.
  3. Press sin, cos or tan, type the angle, then EXE.
  4. For sin⁻¹, cos⁻¹ or tan⁻¹, press SHIFT then sin, cos or tan.

fx-83/85 GT (MODE)

  1. Check DEG mode (not RAD) on screen
  2. sin, cos, tan buttons for ratios
  3. Shift sin/cos/tan for inverse functions

fx-991CW

  1. A small D at the top of the screen means degrees. R means radians.
  2. If you need degrees: SETTINGS → Calc Settings → Angle Unit → Degree, then OK, then AC.
  3. Press sin, cos or tan, type the angle, then EXE.
  4. For sin⁻¹, cos⁻¹ or tan⁻¹, press SHIFT then sin, cos or tan.

Ratio

Choose the form
3:8 = X:12

fx-83GT CW

  1. Press HOME, choose Ratio, then OK.
  2. Choose A:B=X:D or A:B=C:X, then OK. For 3:8 = X:12, choose A:B=X:D.
  3. Enter the known numbers (A = 3, B = 8, D = 12) and press EXE.
  4. The missing value is shown as X.

fx-83/85 GT (MODE)

  1. There is no ratio mode. For 3:8 = x:12, calculate 12 ÷ 8 × 3.
  2. Or write the ratio as a fraction and use the fraction key.

fx-991CW

  1. Press HOME, choose Ratio, then OK.
  2. Choose A:B=X:D or A:B=C:X, then OK. For 3:8 = X:12, choose A:B=X:D.
  3. Enter the known numbers (A = 3, B = 8, D = 12) and press EXE.
  4. The missing value is shown as X.

Prime factors

Enter 84
FORMAT menu
Prime factors

fx-83GT CW

  1. In Calculate, type 84 and press EXE.
  2. Press FORMAT, choose Prime Factor, then OK.
  3. The screen shows 2² × 3 × 7.

fx-83/85 GT (MODE)

  1. If your calculator has FACT, type the number, then press SHIFT then FACT.
  2. Otherwise divide by primes yourself: 84 = 2 × 2 × 3 × 7.

fx-991CW

  1. In Calculate, type 84 and press EXE.
  2. Press FORMAT, choose Prime Factor, then OK.
  3. The screen shows 2² × 3 × 7.

Simultaneous equations

Two unknowns
The coefficients
The solution

fx-83GT CW

  1. The fx-83GT CW has no equation app.
  2. Solve by elimination or substitution, or use the simultaneous equations solver on Maths Vault.

fx-83/85 GT (MODE)

  1. Only if MODE lists EQN and a simultaneous option. Enter the coefficients as prompted.
  2. Otherwise solve by elimination or substitution.

fx-991CW

  1. Press HOME, choose Equation, then OK. Choose Simul Equation, then 2 unknowns.
  2. For 2x + y = 8 and x − y = 1, enter the first row as 2, 1, 8 and the second as 1, −1, 1.
  3. Press EXE. x = 3 and y = 2.
  4. On an fx-991EX, open Equation from MENU, then Simul.

Normal distribution

Choose Normal CD
Area below 1

fx-83GT CW

  1. The fx-83GT CW has no Distribution app.
  2. A-level normal probabilities need the fx-991CW, or a statistics table.

fx-83/85 GT (MODE)

  1. MODE calculators in the fx-83/85 GT class do not have a normal distribution mode.

fx-991CW

  1. Press HOME, choose Distribution, then OK. Choose Normal CD.
  2. For the area below 1 on X ~ N(0, 1): Lower = −9×10⁹⁹ (press (−), 9, ×10^x, 99), Upper = 1, σ = 1, μ = 0.
  3. Press EXE. The screen shows 0.841344746.
  4. On an fx-991EX, open Distribution from MENU.

Vectors

Store VctA
Magnitude

fx-83GT CW

  1. The fx-83GT CW has no Vector app.
  2. The magnitude of (3, 4) is √(3² + 4²). Type that in Calculate. The answer is 5.

fx-83/85 GT (MODE)

  1. There is no vector mode. Work out √(3² + 4²) in the usual calculation screen.

fx-991CW

  1. Press HOME, choose Vector, then OK.
  2. Define VctA with dimension 2. Enter 3 and 4, then OK.
  3. Press TOOLS → Vector Calc → Magnitude, then EXE. The result is 5.
  4. On an fx-991EX, open Vector from MENU.

Derivative and integral

Derivative at x = 3
Integral from 0 to 1

fx-83GT CW

  1. The fx-83GT CW cannot do numerical calculus.
  2. Differentiate or integrate by hand. For x², the derivative at x = 3 is 6, and the integral from 0 to 1 is 1/3.

fx-83/85 GT (MODE)

  1. MODE calculators in this class do not have a derivative or integral template.

fx-991CW

  1. In Calculate, press CATALOG → Func Analysis → Derivative.
  2. For d/dx (x²) at x = 3, fill the template and press EXE. The value is 6.
  3. For an area, CATALOG → Func Analysis → Integration. ∫ from 0 to 1 of x² dx is 1/3.
  4. Press FORMAT and choose Decimal if you want 0.333… On an fx-991EX the ∫ and d/dx templates are shifted keys.
Tip: use the standard form calculator, trigonometry calculator and simultaneous equations solver on Maths Vault to check your calculator working with full written steps.