Command Words: Unlocking Exam Questions

1. The First Clue: Marks Available

Before we even look at command words, the number of marks allocated to a question is your first and most important clue about how much work you need to show.

A common mistake is to write a full page of working for a 2-mark question or to give a single-line answer for a 5-mark question. Both approaches lose time and marks.

To explore this idea, let's watch a short clip from a video by an IGCSE World Topper. He explains this exact point very clearly.

As you saw, a question worth [1] or [2] marks suggests a straightforward process. If you find yourself in a long, complicated calculation, you've likely missed a simpler path. Conversely, a question worth [4], [5], or [6] marks is explicitly telling you: "Show me your step-by-step thinking."

2. The Command Word Dictionary

Now, let's get to the core of the lesson: the command words themselves. These are the specific instructions from the examiner. The Cambridge IGCSE board provides a guide for learners that defines these terms. It's the most reliable source, so we'll start there.

Let's dissect the most frequent and important command words you just read about.

Calculate / Work out

These are the most common instructions. They mean you need to find a numerical answer. You must show the main steps of your calculation. Simply writing down the final answer from your calculator will lose you the "method marks" that are often worth more than the final "accuracy mark."

Write down

This command word is a gift of time! It means the answer can be found directly with little or no calculation. You might be reading a value from a graph, using a result from a previous part of the question, or stating a simple fact. Don't waste time showing work if the question says "Write down".

Sketch

This is a frequent source of confusion. A 'sketch' does not need to be perfectly to scale. It is a freehand drawing that must show the key features of a graph or shape. For a function, this typically means:

• The general shape (e.g., a U-shape for a positive quadratic).
• The points where the graph crosses the x and y axes (the intercepts).
• The coordinates of any turning points (maximums or minimums).

Hence

This word is a strict instruction. It means "using your previous answer". If a question asks you to 'Hence, solve the equation...', you must use the result from the part before. If you solve it using a different method (even if you get the right answer), you will score 0 marks for that part.

3. Your Focus Area: Mastering "Show that" Questions

You've identified "Show that" questions as a weakness. Let's reframe how you see them. Think of them not as a problem to solve, but as a proof to construct. The answer is already given to you; your task is to provide the clear, logical, step-by-step argument that leads to it.

The most important rule for a "Show that" question is: you cannot use the answer in your working. You are trying to get to the answer.

Let's look at the official definition from a Cambridge Teacher's Guide.

Analysing a Common Mistake

Knowing the rule is one thing; seeing how it's applied (and where students go wrong) is even better. We're going back to the Learner Guide to analyse a real exam-style question and a candidate's response.

Let's break down that error. The question was: Show that the distance AB is 375m.

The candidate correctly identified Pythagoras' theorem was needed and wrote:
AB² = 300² + 225² = 140625
AB = 375

The examiner's comment states the candidate "missed out an important step". What was it? They jumped from $A{B}^2=140625$ directly to the answer, $AB=375$.

To get full marks on a "Show that" question, you must be explicit. The complete working should have been:

1. $A{B}^2=300^2+225^2$ (Identifying the correct formula)
2. $A{B}^2=90000+50625$ (Showing the calculation)
3. $A{B}^2=140625$ (Result of the sum)
4. $AB=\sqrt{140625}$ (This is the crucial missing step - showing you are taking the square root)
5. $AB=375$ (Final given result)

This might seem like a small detail, but in a "Show that" question, it's the difference between full marks and losing a mark. You are proving you know the entire process.

4. Key Takeaways and Next Steps

Let's summarise the core principles of today's lesson.

• Check the Marks: Use the mark allocation to judge the depth of working required. High marks mean multiple steps are needed.
• Obey the Command Word: These are direct instructions. 'Calculate' means show your method, 'Write down' means the answer is direct, and 'Hence' means you must use the previous part.
• Treat "Show that" as a Proof: Start with the given information and build a logical, step-by-step chain of reasoning that ends at the given answer. Show every single step, even the "obvious" ones.

In this lesson, we've focused on understanding what the exam questions are asking you to do. To continue building your exam technique, our next lesson will focus on how your work is marked. We will dive into analysing mark schemes to identify exactly how "method marks" (M marks) and "accuracy marks" (A marks) are awarded. This is the next step to turning the exam into a predictable system you can master.