Decomposition involves breaking down a complex problem or system into smaller parts that are more manageable and easier to understand. The smaller parts can then be examined and solved, or designed individually, as they are simpler to work with.

If a problem is not decomposed, it is much harder to solve. Dealing with a complex problem is much more difficult than breaking a problem down into a number of smaller problems and solving each one, one at a time. Smaller problems are easier to understand and can be examined in more detail.

For example, suppose that a crime has been committed. Solving a crime can be a very complex problem as there are many things to consider.

A police officer would need to know the answer to a series of smaller problems:

  • what crime was committed
  • when the crime was committed
  • where the crime was committed
  • what evidence there is
  • if there were any witnesses
  • if there have recently been any similar crimes

The complex problem of the committed crime has now been broken down into simpler problems that can be examined individually, in detail. Once the individual information has been gathered and collated, the police officer may be able to solve the crime.


How might you decompose the complex problem of how to create an app?

  • what kind of app you want to create
  • what your app will look like
  • who the target audience for your app is
  • what your graphics will look like
  • what audio you will include
  • what software you will use to build your app
  • how the user will navigate your app
  • how you will test your app
  • where you will sell your app

These smaller problems, solved individually, may help you to create an app.