How to Get an A* in IGCSE Computer Science

If you're aiming for an A* in IGCSE Computer Science, this guide will show you exactly how to get there. Success in IGCSE Computer Science isn't just about memorising facts — it's about understanding how computers work, solving problems logically, and applying what you've learned in different contexts. In this article, you’ll learn the strategies that top students use to secure the highest grade.

Know what the exam is really testing

IGCSE Computer Science students who get top marks know the difference between learning content and learning how to use that content in an exam. Your first step is to break down the syllabus:

• Learn key terms and definitions

• Understand the structure of both Paper 1 (theory) and Paper 2 (practical/problem-solving)

• Identify the command words (e.g. describe, explain, state)

Turn the syllabus into flashcards or short-answer questions to quiz yourself regularly.

Practice logic and pseudocode every week

Paper 2 in IGCSE Computer Science is where many students drop marks. To get an A*, you need to be confident with algorithms, trace tables, and writing pseudocode.

Here’s a typical pseudocode structure you should be comfortable with:

FOR i ← 1 TO 5

    INPUT score

    total ← total + score

NEXT i

average ← total / 5

OUTPUT average

Don’t just study syntax, practise creating your own algorithms to solve mini problems (e.g. finding the highest number, checking for prime numbers).

Use mark schemes to learn how to write answers

For Paper 1, many of the questions are explain-style or multi-step. Top students know that writing full, precise answers using correct terminology is key.

• Look at past papers regularly

• Study how marks are awarded

• Practice timed answers and self-mark using the official mark scheme

Keep a notebook of model answers and common mistakes to revise from.

Revise actively, don’t just re-read

A* students don't just highlight notes, they interact with the content.

Try:

• Teaching the topic to a friend or family member

• Creating mind maps or flowcharts

• Completing questions from different topics back-to-back

This builds deeper understanding and helps with exam-style thinking.

Common Mistakes to Avoid

1. Ignoring Paper 2 until the end

Many students focus heavily on theory and leave the practical side of the course until the final weeks. Paper 2, however, tests your understanding of algorithms, pseudocode, and logic. If you only practise these topics just before the exam, you won’t be confident enough to score full marks.

To avoid this, practise algorithmic thinking throughout your revision. Use short, timed tasks and past paper questions to build speed and accuracy from the start.

2. Writing vague or incomplete answers

IGCSE Computer Science questions often require specific terminology and detailed reasoning. Students who write general answers without keywords can lose easy marks, even if they understand the topic.

Always read the command word carefully and look at how marks are awarded in the mark scheme. Use precise language and make sure your answers are complete, even for short questions.

3. Revising passively

Highlighting notes or re-reading a textbook might feel productive, but it doesn’t help you remember or apply knowledge. Passive revision leads to gaps in understanding, especially when questions are worded differently from what you’ve seen before.

Switch to active techniques such as answering questions, creating flashcards, or teaching topics to someone else. This makes your revision much more effective and exam-focused.

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