What's covered
Key facts
Ignoring details that don't matter is called abstraction.
Clear, ordered steps make an algorithm easier for others to follow and check.
Breaking a big problem into smaller parts is called decomposition.
Spotting that two problems both need a loop is pattern recognition between those problems.
Step-by-step instructions for solving a problem are called an algorithm.
Abstraction in computing means ignoring detail that is not needed to solve the problem.
Designing an algorithm before coding helps avoid mistakes that would be costly to fix later.
Decomposition is breaking a problem into smaller parts.
Spotting common features between problems is called pattern recognition.
An algorithm is a set of step-by-step instructions for solving a problem.
Sample questions
A taste of the 50 questions in this topic — answers marked. Sign up to practise the full set with spaced repetition.
What does abstraction help us do?
- •Add all possible detail to a problem
- ✓Focus only on what's relevant
- •Make the code run more slowly
- •Use more memory than needed
What does algorithm design mean?
- •Drawing the user interface and choosing the colours of the buttons
- ✓Planning the step-by-step logic that solves a problem before writing any code
- •Testing a finished program with example inputs to find bugs
- •Writing the final program code in Python or another language
Why use decomposition?
- •Smaller parts always run faster on CPUs
- ✓Smaller parts are easier to solve
- •Smaller parts make programs work alone
- •Smaller parts use no memory at all
Why spot patterns in programming?
- •Make all programs identical to each other
- •Reduce the number of variables to zero
- •Remove the need for any kind of testing
- ✓Solve similar problems the same way
Is a recipe an algorithm?
- •No, a recipe has no definite end point
- •No, algorithms must be written in code
- •Yes, because it uses variables and loops
- ✓Yes, it lists ordered steps
An Underground map showing straight lines is abstraction because:
- ✓It ignores the real curved track shape
- •It includes all the train schedules
- •It shows every house along each line
- •It shows the GPS of each station exactly
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