Stretch tasks Computational Thinking

Round 1: Quiz Blitz

1. Removing unnecessary detail to focus on what matters The skill is deciding what is unnecessary for this particular problem.
2. Breaking a problem into smaller sub-problems Each sub-problem is easier to solve, and the solutions are then combined.
3. Abstraction The look of a building does not help find a route, so it is removed.
4. Road lengths; One-way streets Distances, junctions and one-way systems decide the route. The rest is noise.
5. False Abstraction removes detail. Decomposition splits the problem up.
6. Parts can be worked on by different people at once; Each part can be tested on its own Smaller parts are easier to understand, share out, test and reuse.
7. Fill the kettle → Switch the kettle on → Wait until it boils → Pour the water into the mug Order is not decoration: you cannot pour before the kettle boils.
8. algorithmic thinking Algorithmic thinking turns a decomposed problem into steps a computer can run.
9. Finite An algorithm that never stops never gives an answer.
10. The material does not affect the legal moves Abstraction keeps only the details that affect the problem.
11. True The weather does not matter to a satnav, but it is everything to a weather app.
12. Make the game work A useful sub-problem is small and specific enough to write and test on its own.

Round 2: Quick Fire

1. • Abstraction is removing unnecessary detail
   • A satnav keeps the roads and junctions but leaves out buildings, because they do not affect the route
   Model answer

   Abstraction is removing unnecessary detail so you can focus on what matters. A satnav keeps the roads, junctions and distances, but leaves out what the buildings look like, because that does not help find a route.

2. • Load the questions from a file
   • Display each question and its options
   • Accept and validate the player's answer
   • Check whether the answer is correct
   • Keep and update the score
   • Move on, and show the final result
   Model answer

   Load the questions from a file. Accept and validate the player's answer. Keep and update the score.

3. • Each part is easier to understand and solve
   • Different people can work on parts at the same time
   • Each part can be tested on its own
   • Parts can be reused in other programs
   Model answer

   Each part is easier to understand than the whole problem, and each part can be tested on its own, so bugs are easier to find.

4. • Identifying the steps needed to solve a problem
   • And putting them in the correct order
   Model answer

   Algorithmic thinking is identifying the steps needed to solve a problem and putting them in the correct order.

Round 3: Big Think

1. • Decomposition breaks the problem into smaller sub-problems
   • Sensible sub-problems, such as logging in, showing free slots and confirming
   • Each part can be written and tested separately, possibly by different people
   • Abstraction removes unnecessary detail
   • It keeps what matters, such as teachers, rooms and time slots
   • It leaves out what does not matter, such as what the teachers look like
   • This makes the program simpler and quicker to build
   Model answer

   Decomposition breaks the problem into smaller sub-problems, such as logging in, showing each teacher's free slots, choosing a time, confirming the appointment by email and letting parents cancel. Each part can be written and tested separately, possibly by different people. Abstraction removes unnecessary detail: the program needs each teacher's name, room and time slots, and the student's name, but not what the teachers look like or the colour of the classrooms. That makes the program simpler and quicker to build, because it can focus on what matters.

2. • Unambiguous: every step has exactly one meaning, so it cannot be misread
   • Ordered: steps that depend on earlier results must come after them
   • Complete: no steps are missing
   • Finite: it must eventually stop
   Model answer

   An algorithm must be unambiguous, so every step has exactly one meaning and cannot be misinterpreted. It must be correctly ordered, because steps that depend on earlier results have to come after them, such as pouring the water only after the kettle boils. It must be complete, with no missing steps, or the task will not be finished. And it must be finite: it has to stop eventually rather than running forever.

This or That

1. Decomposition Breaking a problem into smaller parts is decomposition.
2. Abstraction Colour does not affect traffic flow, so the detail is removed.
3. Check whether the answer is correct A good sub-problem is specific enough to write and test on its own.
4. Abstraction Passengers need the order of stations and the lines, not the real geography.
5. Yes: later steps depend on earlier ones A computer follows steps exactly as written, so order is part of the algorithm.
6. Finite Finite means it eventually stops.
7. Why it does not matter The mark is for explaining why the removed detail is not needed.
8. Decomposition Separate sub-problems can be shared out across a team.

Memory Match

• A 4 Abstraction: Removing unnecessary detail
• B 5 Decomposition: Breaking a problem into smaller parts
• C 1 Algorithmic thinking: Ordering the steps to solve a problem
• D 3 Sub-problem: One smaller piece of a bigger task
• E 6 Finite: An algorithm that eventually stops
• F 2 Unambiguous: Every step has exactly one meaning

Sort It

1. Algorithmic thinking Checking that every step has exactly one meaning A good algorithm is unambiguous.
2. Algorithmic thinking Making sure the steps eventually stop A good algorithm is finite.
3. Decomposition Testing each part of a program on its own Small, separate parts can be tested independently.
4. Abstraction A satnav ignores what the buildings look like Removing detail that does not affect the route.
5. Abstraction Keeping only the details that matter That is the definition of abstraction.
6. Decomposition Giving each part of a project to a different programmer Decomposition lets a team work on separate parts at once.
7. Algorithmic thinking Writing the steps to solve a problem in order That is the definition of algorithmic thinking.
8. Algorithmic thinking Making sure the kettle boils before the water is poured Putting the steps in the right order.
9. Decomposition Splitting a quiz game into loading, asking and scoring Breaking the problem into sub-problems.
10. Abstraction An Underground map leaves out real distances Passengers only need the stations and lines.
11. Decomposition Breaking a big problem into smaller sub-problems That is the definition of decomposition.
12. Abstraction A chess program ignores what the pieces are made of The material has no effect on the legal moves.