AQA A-Level Computer Science Paper 1, June 2025: Question 2

2 marks · Easy difficulty · Short Answer

Define the term decomposition.

Practise this question

Question

Question 02 asks students to 'Define the term decomposition.' worth 2 marks. Beneath this line, the start of another statement or question reads: 'Dijkstra’s algorithm is an example of a breadth-first traversal algorithm.'
Question text

02 Define the term decomposition.

[2 marks]

Dijkstra’s algorithm is an example of a breadth-first traversal algorithm.

Mark scheme

Show the mark scheme Mark scheme for question 02 shows 2 marks allocated for AO1 knowledge. Mark point 1: 'Splitting a problem into smaller sub-problems;'. Mark point 2: 'So that each sub-problem accomplishes an identifiable task, which might itself be further divided // Repeating this process until each sub-problem performs a single task;'.

Question Marks

02 All marks AO1 (knowledge) 2

Splitting a problem into smaller sub-problems;

So that each sub-problem accomplishes an identifiable task, which might itself be

further divided

//

Repeating this process until each sub-problem performs a single task;

How to answer it

AQA A-Level Computer Science: Defining Decomposition

What this question tests

This question assesses AO1 (Demonstrate knowledge and understanding) of core computational thinking principles. Specifically, it tests your ability to provide a precise, two-part technical definition of problem decomposition beyond simple colloquial terms.

Question 02 • 2 Marks • AO1

Question 02

Define the term decomposition.

✅ Mark Scheme Answers

Award 1 mark per distinct point (up to 2 marks):

  • Mark 1: Breaking down / splitting a problem into smaller (sub-)problems.
  • Mark 2: So that each sub-problem accomplishes an identifiable task (which might itself be further divided)
    OR
    Repeating this process until each sub-problem performs a single / individual task.

💡 Key Knowledge

  • Computational Thinking Pillar: Decomposition is one of the four cornerstones alongside abstraction, pattern recognition, and algorithm design.
  • Top-Down Design: Large systems are recursively broken down into manageable sub-routines, functions, or modules.
  • Modularity: Sub-problems can be developed, tested, and maintained independently, often by different programmers.

🧠 Exam Technique & Scoring 2/2

  • Notice the mark allocation: A 2-mark definition requires two distinct aspects.
  • Aspect 1 (Action): What do you do? → Break down a complex problem into smaller parts / sub-problems.
  • Aspect 2 (Condition / Extent): To what degree or purpose? → Until each sub-problem achieves a specific, identifiable single task.
  • Always use formal technical terminology like sub-problems or tasks rather than vague words like "bits" or "chunks".

❌ Common Misconceptions

  • Stopping at 1 mark: Stating only "breaking a problem into smaller parts" is a common GCSE-level response that earns only 1 mark at A-Level.
  • Confusing with Abstraction: Defining it as "removing unnecessary detail to focus on key elements".
  • Biology / Everyday usage: Mentioning organic decay or physical breakdown of matter.
  • Vague phrasing: Saying "making the problem easier to solve" without explaining how or the degree of division.
Examiner Insight: Full marks were awarded to candidates who recognized that decomposition is recursive—sub-problems are divided repeatedly until they represent self-contained, individual tasks that can be addressed directly by a sub-routine or function.

Topics

4.4 Theory of computation · 4.4.1 Abstraction and automation

Question and mark scheme from the AQA A-Level Computer Science examination, Paper 1, June 2025. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.