Computational thinking

Learn about computers and real world problem solving.

This lesson includes:

  • a video to help you understand algorithms
  • a video to help you understand problem solving
  • three activities to try out


Computational thinking is breaking down a problem and finding solutions a computer can understand.

There are four key cornerstones to computational thinking:

  • decomposition - breaking down a complex problem or system into smaller, more manageable parts.
  • pattern recognition – looking for similarities among and within problems.
  • abstraction – focusing on the important information only, ignoring irrelevant detail.
  • algorithms - developing a step-by-step solution to the problem, or the rules to follow to solve the problem.
The four cornerstones of computational thinking


Watch this film to find out more about algorithms.

An algorithm is a clear sequence of instructions with a start, a finish, and usually some decisions in the middle.

A teenage programmer creates an algorithm to teach her computer a dance routine.


In this film we see how a task like 'Shopping for groceries' can seem simple to us.

But it is a task that can be broken down into smaller tasks using decomposition.

Shopping for groceries is broken down into simple steps using decomposition.

Shopping for groceries requires lots of smaller tasks to be solved.

We see in the film that a computer needs the problem put into simple logical steps so it understands what to do.

With a clear set of ordered instructions, the computer goes to the shop, collects the items, pays for them - but returns without them.

The programmer has forgotten to tell him to bring the shopping home in her instructions.

She amends her code, including all the necessary instructions.


Activity 1

Take the Bitesize Computational Thinking test to check how much you have learned.

Activity 2

Test your knowledge of algorithms and variables with this quiz from SAM Learning.


Where next?

In this lesson you have learnt about computational thinking and decomposing problems.

Click on the links below for more help with computing:

Watch more clips about computational thinking in the series How to Think Like a Computer.

There's more to learn

Bitesize Daily lessons
KS3 Computer Science
Jobs that use Computing and ICT
KS3 Computer Science
Practise coding with Scratch
Play CBBC games