Having a calculator in the GCSE maths exam does not mean the marks come automatically — students who use their calculator confidently and strategically consistently outperform those who use it only for basic arithmetic. Knowing your calculator's functions, inputting values correctly, and building a checking habit are skills that need deliberate practice before exam day.
Which papers allow a calculator at GCSE maths?
GCSE maths consists of three papers. The structure is the same for AQA, Edexcel, and OCR:
| Paper | Calculator allowed? | Marks | Duration |
|---|---|---|---|
| Paper 1 | No | 80 | 1 hour 30 min |
| Paper 2 | Yes | 80 | 1 hour 30 min |
| Paper 3 | Yes | 80 | 1 hour 30 min |
Two of the three papers are calculator papers, so your calculator technique matters significantly. The calculator you bring must be a scientific calculator — a basic four-function calculator is not sufficient for GCSE maths. The Casio fx-85GT CW (or its predecessors) is the most widely used calculator in UK schools and the one this article refers to throughout.
What calculator functions must I know for GCSE maths?
Many students know only the basics: add, subtract, multiply, divide, and perhaps the square root button. GCSE maths requires fluency with several more functions:
| Function | Button or method | When you need it |
|---|---|---|
| Fractions | a b/c or fraction template |
Exact answers involving fractions |
| Powers and roots | x², x³, ^ (or x□), √, ∛ |
Indices, standard form, surds |
| Standard form | Enter as 1.5 × 10^6 using ×10^ key |
Standard form calculations |
| Trigonometry | sin, cos, tan and their inverses |
Right-angled triangles, bearings |
| Memory | M+, M-, MR, MC |
Storing intermediate answers |
| ANS key | Ans |
Re-using the last calculated result |
| π (pi) | π key |
Circle calculations |
| Recurring decimals | Use fraction function then S↔D |
Converting recurring decimals |
Practice each function on its own before the exam so pressing it feels automatic under pressure.
How do I input fractions and mixed numbers correctly?
A common error on GCSE papers is inputting fractions as divisions (typing 3 ÷ 4 instead of using the fraction function) and then losing the exact form needed for the answer. To input a fraction:
- Press the fraction key (it usually looks like a box over a box, or
a b/c). - Type the numerator, press the right arrow to move to the denominator, type the denominator.
- Press
=to calculate.
To convert between a fraction and a decimal, use the S↔D (or Format) key after calculating. If the question asks for an exact answer, leave it as a fraction; if it asks for a decimal, convert it.
Worked example: Calculate ³⁄₇ + ⁵⁄₉.
- Input using the fraction function: 3/7 + 5/9 =
- Calculator gives: 62/63 (the exact fraction — no rounding needed)
- This is the correct form for an "exact answer" question.
If you had typed 3 ÷ 7 + 5 ÷ 9 the calculator would give 0.9841…, which loses the exact value and will not match the mark scheme.
How do I use the ANS key and memory to avoid errors?
Copying a long decimal from one part of a calculation to the next by hand is one of the most common sources of error in GCSE maths. The ANS key and memory functions eliminate this risk.
Using ANS: After any calculation, pressing Ans in the next calculation uses the complete stored result — not a rounded version you typed. For example:
- Calculate the value of
sin(37°)→ the calculator gives0.6018... - Rather than typing
0.60in the next step (which introduces rounding error), pressAnsto carry the full value forward.
Using memory: When you need to store a value mid-calculation:
- Calculate the value.
- Press
M+to store it in memory. - Continue with other steps.
- Press
MR(memory recall) when you need that value again.
This is particularly useful in questions involving the cosine rule or multi-step percentage calculations.
What is a good checking strategy for calculator papers?
Having a calculator does not mean every answer is automatically correct — input errors are common under exam pressure. Build a two-step checking habit:
- Estimate before you calculate. Before pressing
=, estimate roughly what the answer should be. If the calculation is47.3 × 8.9, estimate50 × 9 = 450. If your calculator gives42.097, you know immediately something is wrong — and you find you miskeyed4.73instead of47.3. - Use a different method to check. For multiplication, check by division: if
a × b = c, thenc ÷ bshould givea. For a percentage calculation, sanity-check by asking whether the answer is bigger or smaller than the starting number in the expected direction.
How should I practise my calculator technique before the exam?
- Use the exact same calculator model in revision that you will use in the exam. Different models have different button layouts, and muscle memory matters.
- Practise completing past paper calculator questions with the intention of never writing down intermediate steps — force yourself to use the ANS key and memory.
- Run through the key function list above at the start of each revision session, spending two minutes pressing each function type to warm up.
Frequently asked questions
Can I use any scientific calculator in the GCSE maths exam?
Yes, any non-programmable scientific calculator is permitted. Graphical calculators and calculators with a computer algebra system (CAS) are not allowed. The invigilator may inspect your calculator before the exam. If in doubt, check your exam board's equipment list — AQA, Edexcel, and OCR all publish guidance on permitted calculators.
Should I always use my calculator, or are there times to work by hand?
For simple calculations — adding small whole numbers, multiplying by 10, dividing by 5 — it is often faster and less error-prone to work mentally. Reserve the calculator for complex arithmetic, trigonometry, and anywhere that rounding must be avoided. Using the calculator for 2 + 3 wastes time and creates opportunities to mis-key.
What should I do if my calculator gives a strange answer I do not expect?
Check whether it is in the correct mode. GCSE maths requires degree mode for trigonometry (not radians — if your calculator is in radian mode, sin(30°) gives 0.988 instead of 0.5). Look for DEG, D, or ° on the screen to confirm degree mode; if you see RAD or R, press the mode or setup button to switch.
My answer is a surd like √45 — should I simplify it?
Yes. Simplify surds where possible: √45 = √(9 × 5) = 3√5. Your calculator can help you check: type √45 and press S↔D — it will display 3√5 directly on many Casio models. If the question asks for an exact answer, leave it in surd form. If it asks for a decimal, press S↔D again to convert.
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