Computational Thinking Skills — abstraction and decomposition

By the end of this lesson

By the end you can explain what abstraction is and why it is useful, produce a simple abstract model of a real-world system, and describe how decomposition breaks a problem into sub-problems that become procedures or functions.

What is abstraction?

Abstraction is the process of filtering out — ignoring — the details that don't matter for the problem at hand, so you can focus on what does. You build an abstract model that captures only the essential features.

Everyday example: a tube map. It shows stations and connections but ignores exact geography, distances, and street layouts. For the purpose of planning a journey, those details are noise; the abstract model (the map) is far more useful than a satellite photo.

In computing, abstraction appears everywhere:

Variables hide memory addresses.
Procedures/functions hide a sequence of steps behind a name.
Classes/objects hide internal data and expose only behaviour.
APIs hide implementation behind a stable interface.

The syllabus expects you to be able to:

State the purpose and benefits of abstraction.
Produce an abstract model by including only essential details.

Worked example: Modelling a library system

A library wants software to track books, borrowers, and loans. Produce an abstract model.

Have a go first?

Quick check — abstraction

In your own wordsQuestion 1 · Recall

Fill in the blanksQuestion 2 · Apply

Answer the 2 questions above to continue.