Problem Solving Logic

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Overview

• Subject: Technology
• Key Stage: KS3 (Year 9)
• Topic: Algorithms
• Lesson Duration: 40 minutes
• Class Size: 10 students
• Level: According to the National Curriculum in England for Computing — “design, use and evaluate computational abstractions that model the state and behaviour of real-world problems and physical systems.”
• Focus: Developing logical thinking through algorithm design and decomposition with an engaging real-life scenario.

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Learning Objectives

By the end of this lesson, students will be able to:

1. Define what an algorithm is and describe its purpose.
2. Decompose a real-world problem into steps using algorithmic thinking.
3. Create, represent and test a simple algorithm using flowcharts and pseudocode.
4. Evaluate their algorithm for efficiency and clarity.

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Required Materials

• Mini whiteboards and pens (for quick fire ideas)
• Printed scenario cards (see below)
• Large A3 flowchart templates
• Markers and sticky notes
• Laptops/tablets (optional for extension)
• Timer
• Printable assessment rubrics (for peer review)

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Key Vocabulary

• Algorithm
• Decomposition
• Abstraction
• Pseudocode
• Flowchart
• Efficiency

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Curriculum Links

This lesson supports the following KS3 Computing aims:

England KS3 National Curriculum – Computing

• Understand several key algorithms that reflect computational thinking.
• Use logical reasoning to compare the utility of alternative algorithms for the same problem.
• Design, use and evaluate computational abstractions that model the state and behaviour of real-world systems.

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Lesson Breakdown

⏱ Starter – 5 minutes

Activity: “Algorithm Guess Who?”

Quick-fire whiteboard game where students must write down what they believe an algorithm is in 15 words or fewer.
Then, each student reads someone else's response aloud (without naming the author). As a class, they vote on the strongest definition and discuss why.

Purpose: Activates prior knowledge, promotes peer discussion, clarifies misconceptions.

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🧠 Main Activity – 25 minutes

Part 1 – 10 minutes

Decomposition Challenge: “The Crashed Delivery Drone”

Scenario: A delivery drone carrying five packages has crashed in the middle of the school. It dropped the packages in various locations. Your team’s job is to write an algorithm (step-by-step solution) to help another robot retrieve them efficiently.

In Teams (2–3 students):

• Identify sub-problems (decomposition)
  • How does the robot know where to go?
  • What’s the most efficient route?
  • What to do if a location is unreachable?

Tools: Scenario card, sticky notes, large surface.

Part 2 – 10 minutes

Algorithm Design: Flowcharts & Pseudocode

Now teams draw a flowchart of their retrieval plan, including conditions like "if package not there → go next."

Then they write complementary pseudocode beside it.

Example Pseudocode Snippet:

START
SET list_of_packages = [P1, P2, P3, P4, P5]
FOR each package in list_of_packages:
   IF accessible:
       retrieve(package)
   ELSE:
       mark_as_lost(package)
END

Encourage:

• Clear logic
• Simple steps
• Handling errors or obstacles

Part 3 – 5 minutes

Peer Evaluation (The “Robo Review”)

Teams swap their algorithms with another group. They simulate the algorithm using a small whiteboard maze or by acting physically (for kinaesthetic learners).

Class provides feedback using printed rubrics:

• Clarity
• Logical structure
• Efficiency
• Error handling

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💬 Plenary – 5 minutes

Discussion Prompt: How Do Algorithms Impact You Daily?
Facilitated circle time-style talk:

• Can you think of one algorithm you used this morning?
• Where might algorithms ‘hide’ in regular life?
• Why is understanding them important?

End with a short reflection on:
🟡 “One Thing I Learned”
🟡 “One Thing I’m Curious About”

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Differentiation

• Support: Provide scaffolded card prompts for students needing guidance in decomposition and pseudocode.
• Challenge: Invite high-achieving students to compare their algorithm’s efficiency (number of steps) against others and refine.
• SEND: Use visual aids and tactile movement (e.g. moving tokens around a mockup map) to support accessibility.

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Cross-Curricular Links

• Mathematics: Logical sequencing, decision trees.
• Geography: Mapping/package retrieval planning across ‘terrains’.
• English: Writing clear instructions mimics procedural writing.

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Assessment for Learning

• Formative: Live questioning during group work, observations.
• Peer: Structured feedback sessions during Robo Review.
• Summative: Optional homework — write a simple algorithm to make a cup of tea (using pseudocode or flowchart).

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Extension / Homework Idea

💡 Creative Coding Twist (Optional ICT Integration)
Challenge students to convert their pseudocode into visual block-based code using software like Scratch or Python's Turtle module (for more confident groups).

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Teacher Reflection Prompt

How did students approach the decomposition stage?
Did they show adaptability when peer reviewing or modifying their algorithms?

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Final Note for Teachers

This lesson is designed to not only meet the curriculum but also foster computational thinking that resonates in everyday logic and creativity. With the small class size (10 students), there is a unique opportunity for deep discussion, playful simulation and a highly personalised flow to the session.

Consider recording snippets of student algorithm walkthroughs (with consent), as these make excellent evidence for student progress and computational language use!

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Prepared by:
Technology KS3 Specialist AI Co-Planner
UK Curriculum-Focused Collaboration