Top 5 Mistakes in IGCSE Maths (And How to Avoid Them)
We all know the frustration of the IGCSE experience.
After all, you leave the examination and think, “I know this stuff.”
Then you get the results back and somehow the grade isn’t worth it.
The bad news is this: In the Cambridge IGCSE Mathematics exam, you lose marks, not only for questions you don’t know. You lose them for what you thought you knew.
Ones and zeroes. Ruthlessly so.
Additional steps, ambiguities in question wording or a rounding error… these are the silent assassins between a good B and the elusive A*.
Here, we’ll identify the biggest blunders in IGCSE Maths, from forfeiting method marks to the time wasters, and how to avoid them so you can walk into your next exam with confidence.
The Peril of Missing Method Marks (They “Didn’t Show any Working”)
Mental Math Overconfidence
Some students are mental calculators.
They work problems out mentally, calculate the final answer – and if it is incorrect, they receive no mark whatsoever. No pity, no marks.
The rule is simple: if they can’t see it, they can’t mark it.
If you can get right, but don’t write down how, it’s not there.
Skipping Steps
This is subtler than it sounds.
The key to the formula shouldn’t be “worked out”; it should be written down.
With a 3-mark question, for instance:
- Work is there, 2 marks assured
- Final answer wrong → you get some marks
No working? You’re left with nothing.
Misinterpreting the Question
Not Reading Carefully
Most mistakes are not made because it’s hard. They come from speed.
Students skim – and overlook details such as:
- Finding radius instead of diameter
- Finding mean instead of median
A word is one word too far.
Ignoring Key Constraints
Cambridge loves precision:
- “Round to 3 significant figures”
- “Give your answer to 1 decimal place”
Do this wrong, and you get marks taken off your answer.
Here’s how to fix it:
Slow down. Underline keywords. Follow the instructions.
Calculator and Calculation Blunders
Premature Rounding
Rounding too soon is like laying a house on crooked foundations.
Errors accumulate, until the final answer goes awry.
Best practice:
👉 Don’t over-write numbers
👉 Round at the end, only
The “Wrong Mode” Error
The eloquent assassin of trigonometry.
If you’re using radians on your calculator rather than degrees, you’re going to get completely the wrong answer – no matter how perfect your technique.
Look at the screen before any trig question:
👉 DEG mode ON
Missing Brackets
A small symbol, big deal.
- -3² = -9
- (-3)² = 9
Those two brackets will change the sign.
Detail matters, the devil is in the… well, you know.
Poor Exam Time Management
Getting Stuck on Hard Questions
It takes 15 minutes to complete a 2-mark question?
A smarter approach:
👉 Rule of thumb: 1 mark = 1 minute
If you can’t get it, move on. Try again later.
Leaving Questions Blank
This is the simplest problem to correct (and most humiliating).
Even if you don’t know:
- Write the formula
- Show the first step
That can help you get method marks.
Writing nothing isn’t worth any marks.
How Students Can Steer Clear in the Lead Up to the Exam
It’s not more study. It’s studying smarter.
Active Practice Wins
Studying notes looks like studying.
To learn, do:
- Doing IGCSE Maths past papers
- Practise under pressure
- Preparing you for the pressure
Use the Mark Scheme
Learn to think like an examiner to think like an A* student.
Examiner mark schemes tell you:
- What earns marks
- What gets ignored
- What’s decent and what’s outstanding
Here is where the strategy kicks in.
The Bottom Line is Knowledge
Knowledge is not always the difference between a B and an A*.
It’s awareness.
Sometimes the barrier is easily avoidable eg leaving out steps, misreading the questions, using a calculator carelessly.
But recognise them, and you can avoid them.
Want to Stop Losing Marks?
If you can’t figure out where your marks are dropping, you’re not the only one – and you don’t have to figure it out alone.
At Orient Academy in Cyberjaya, subject experts conduct pre-testing and develop learning plans to identify just where you lose marks (and fix it, once and for all).
👉 Whether with the ORIENT Integrated Series (OIS) or the Workshop Series (OWS), we teach students not only to learn Maths, but to pass the exams.
Register for your Free Academic Consultation to track your IGCSE Maths.
