What Examiners Want to See in Your Working

The Examiner Is on Your Side

Here is something most students do not realise: IGCSE Maths examiners are not trying to catch you out. They are actively looking for opportunities to give you marks. Every correct step, every valid method, every piece of correct reasoning is a potential mark. Your job is to make that reasoning visible.

The problem is that many students hide their best work. They do calculations in their head, skip steps they think are obvious, and present only their final answer. When that answer is wrong, the examiner has nothing to reward. When the answer is right, the student got lucky — but luck runs out.

Understanding what examiners want to see allows you to present your working in a way that maximises your marks on every single question.

The Formula-Substitution-Answer Structure

For most IGCSE Maths questions, examiners want to see three things:

1. The formula or method you are using

Write the general formula before substituting any numbers. This shows the examiner you know which method to apply and earns you the first method mark.

Example: “Using Pythagoras’ theorem: a² + b² = c²”

2. The substitution of values

Show the numbers being placed into the formula. This is often where the second method mark is awarded.

Example: “5² + 12² = c²”

3. The calculated answer

Show the arithmetic and state the final answer clearly.

Example: “25 + 144 = c², c² = 169, c = 13”

This three-step structure works for:

Trigonometry questions (write SOH CAH TOA or the sine/cosine rule, substitute, solve)
Area and volume questions (state the formula, substitute measurements, calculate)
Algebraic problems (state the equation, show rearrangement steps, give the answer)
Statistical calculations (write the mean/standard deviation formula, substitute, compute)

Showing “Enough” Working

A common question from students is “How much working should I show?” The answer depends on the number of marks available.

For a 1-mark question: Usually just the answer is sufficient. These questions typically say “Write down” or “State.”

For a 2-mark question: Show at least one step of working plus the final answer. The working earns the method mark; the answer earns the accuracy mark.

For a 3-mark question: Show at least two steps of working plus the final answer. Common structures: formula, substitution, answer; or setup, simplification, answer.

For 4+ mark questions: Show every significant step. Each step potentially earns a mark. Skipping steps risks losing marks if your final answer is wrong.

A useful rule of thumb: the number of lines of working should be at least equal to the number of marks minus one. So a 4-mark question should have at least 3 lines of working plus the final answer.

What Counts as a “Step”

Not everything you write counts as a step for marking purposes. Here is what examiners recognise as mark-worthy steps:

Writing down a correct formula or equation
Substituting values into a formula
Correctly rearranging an equation
Performing a significant simplification
Drawing a correct diagram with labels
Stating a geometric reason (e.g., “alternate angles are equal”)
Converting between forms (e.g., fraction to decimal, standard form to ordinary number)

What does NOT usually count:

Rewriting the question
Writing down the formula sheet entries without applying them
Intermediate arithmetic that does not represent a mathematical step
Crossing out and restarting (though the examiner may look at crossed-out work if your final answer is wrong)

Reasons and Explanations in Geometry

Geometry questions often require you to state reasons for your calculations. Simply writing the numerical answer is not enough — you need to name the geometric property you are using.

Examples of acceptable reasons:

“Angles in a triangle sum to 180°”
“Opposite angles of a cyclic quadrilateral sum to 180°”
“Alternate angles are equal”
“The angle in a semicircle is 90°”
“Tangent to a circle is perpendicular to the radius at the point of contact”
“Base angles of an isosceles triangle are equal”

Each reason you state correctly typically earns an independent mark (B1). Missing the reason means missing the mark, even if your numerical answer is correct. This is one of the most common sources of lost marks in geometry questions.

Units and Rounding

Examiners pay attention to:

Units: If the question specifies units (cm, m², km/h), include them in your answer. Some mark schemes specifically require units for the accuracy mark.

Rounding: Follow the question’s instructions exactly. “Give your answer correct to 3 significant figures” means exactly that — not 2, not 4. If no rounding instruction is given, give an exact answer or use 3 significant figures as a default.

Premature rounding: This is when you round intermediate answers during a multi-step calculation. It introduces errors that compound through subsequent steps. Always keep full precision in intermediate calculations and only round the final answer.

The “Therefore” Chain

For multi-step problems, examiners want to see a clear logical chain where each step follows from the previous one. Use connecting language or symbols:

“Therefore…” or the ”∴” symbol
“So…”
“This gives…”
Equals signs connecting equivalent expressions

Avoid leaps in logic. If there is a gap between two lines of your working, the examiner might wonder how you got from one to the other. Fill in the gaps, even if the step seems obvious to you.

What Examiners Do Not Want to See

Just as there are things that earn marks, there are things that waste your time or actively lose marks:

Long written explanations where algebra would be clearer. Let the maths speak.
Multiple attempts without crossing out. If you change your approach, cross out the old working so the examiner knows which version to mark.
Equals signs between unequal things. Writing “5x + 3 = 5x = 8 = x” is mathematically incorrect and confuses the examiner.
Answers without the question number. Make sure each answer is clearly labelled with its question and part number.
Illegible handwriting. If the examiner cannot read a digit, they will assume it is wrong. Write clearly, especially the numbers 1, 4, 7, and 9, which are commonly misread.

Presenting Answers in the Required Form

Pay close attention to how the question asks you to present your answer:

“Give your answer as a fraction” — do not give a decimal
“Give an exact answer” — leave π, surds, or fractions in your answer; do not round
“Give your answer in standard form” — must be in the form a × 10ⁿ where 1 ≤ a < 10
“Simplify your answer” — reduce fractions, collect like terms
“Give your answer in its simplest form” — factorise or simplify fully

Giving a correct numerical answer in the wrong form can cost you the accuracy mark. It is an entirely preventable loss.

Practice Exercise

Take a past paper you have already completed and remark it using the official mark scheme. For each question, ask:

Did I show enough working for the method marks?
Did I state reasons where required?
Did I give my answer in the required form?
Did I include units where needed?
Could an examiner follow my working without guessing?

This exercise reveals gaps in your presentation that you can fix before the real exam.

Summary

Examiners want to see clear, logical, step-by-step working that demonstrates your mathematical understanding. Use the formula-substitution-answer structure, show working proportional to the marks available, state geometric reasons, follow rounding and form instructions, and make your final answer unmistakable. These habits transform your paper from a guessing game into a mark-earning machine.

Get Expert Help with IGCSE Maths

A specialist IGCSE Maths tutor can review your working and show you exactly how to present solutions that earn maximum marks. Learn to think like an examiner and never leave marks on the table.

Book a Free Trial Class | WhatsApp Us