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Algorithms

Abstraction, decomposition and algorithmic thinking

  • 3 things to know
  • J277/02

Overview

Computational thinking, abstraction and decomposition with worked examples, algorithmic thinking, what an algorithm is, and how the principles work together to solve a problem.

What you need to know

Answer each one before you reveal it.

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Key term

What are the benefits of decomposition?

Key term

A school wants a program to book parents' evening appointments. Give one example of each principle of computational thinking.

Key term

What is computational thinking?

Questions from this subtopic

Each one with the model answer underneath.

  1. 1

    What is computational thinking?

    Model answer

    Computational thinking is a way of analysing a problem so that a computer can help to solve it. The three principles are abstraction, decomposition and algorithmic thinking.

  2. 2

    Define abstraction.

    Model answer

    Abstraction is removing detail that is not needed to solve a problem. Only the details that affect the solution are kept.

  3. 3

    Why is abstraction useful when a problem is being defined?

    Model answer

    Abstraction makes a problem simpler, so the programmer can focus on what matters. A simpler model is quicker to design, code and test.

  4. 4

    A program predicts where a snooker ball will travel after it is struck. Which details would abstraction keep and which would it remove?

    Model answer

    The model keeps the ball's position, speed and direction, and the angles of the cushions. Details such as the colour of the cloth and the players' names are removed.

  5. 5

    How does a sat nav app use abstraction?

    Model answer

    A sat nav shows roads, junctions and the route as simple lines and symbols. Buildings, trees and most scenery are left out because they do not affect the journey.

  6. 6

    What can go wrong if abstraction removes too much detail?

    Model answer

    A model that ignores an important detail gives inaccurate results. A weather forecast that left out wind speed would make poor predictions.

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