Why Calculator Skills Matter
Your scientific calculator is like a professional tool — it's only useful if you know how to use it properly. In IGCSE maths exams, having strong calculator skills can be the difference between getting the right answer and making careless mistakes.
The reality: You will spend hours of your life in exam rooms using a calculator. Spending a few hours now learning to use it well is one of the best investments you can make for your grade.
Here's what you need to understand:
- Scientific calculators have many special functions — square roots, powers, trigonometry, standard form, fractions — that are essential for extended maths
- Different calculator models work differently — yours might access functions using SHIFT, while someone else's uses INV. You must know YOUR specific model
- The most common model is the Casio fx-83GT (or newer versions like the GTX Classwiz), and these notes focus on that, but the principles apply to any scientific calculator
- You'll use these skills in other subjects too — Physics, Chemistry, and Biology all require calculator competence
- Many students get these settings wrong and don't notice — your calculator might be in radians mode (measuring angles differently) and you won't realise until your trig answers are completely wrong
Most important thing you can do right now: Find your calculator's instruction manual (usually available online) and spend 30 minutes learning where each function is. Seriously. Do this before anything else.
Setting Up Your Calculator Correctly
Before you do a single calculation, your calculator needs to be set up correctly. An incorrectly configured calculator will give you wrong answers, and you won't even know it.
The Three Critical Settings
These Must Be Right
1. MODE: Should be MATH (not COMP, not REAL, not anything else)
Look for a button marked 'MODE'. Press it until you see the word "MATH" at the top of your display (or sometimes there's a symbol). Most calculators default to MATH, but check. This mode allows you to work with fractions, exact answers, and sophisticated operations.
2. ANGLE UNIT: Must be DEGREES (not RADIANS)
Press MODE, then look for SETUP or SETTINGS. Find the "Angle" option and make sure it's set to "Deg" or "Degree". You should see a small "D" symbol at the top of your display. Radians is for university-level maths. For IGCSE, you always use degrees. If you calculate sin(45°) in radians mode, you'll get a completely wrong answer.
3. ANSWER TYPE: Know how to switch between Exact and Approximate
In MATH mode, press the "S⇔D" button (or "=" in some models). This switches between exact answers (fractions, surds, multiples of π) and approximate answers (decimals). You need both: exact answers for pure algebra, decimals for applications. Learn to toggle between them.
Before Every Exam: RESET
Examiners recommend this because one small accidental change ruins everything. Before you enter the exam hall:
- Find your calculator's RESET function (varies by model — check the manual)
Exam Day Tips