Teacher guide · Think Lab · Medium · about 35 min

🧮 Perimeter Park Builder

Pupils practise problem solving through "Perimeter Park Builder": Measure fences and design a tiny park.

Lesson guide

1. 1. Hook · 5 min

   Show the 🧮 mission title and read the opening: "A rectangle is 6 m long and 3 m wide. Its perimeter?". Take three quick guesses.

2. 2. Model · 5 min

   Think aloud through the first step together. Use Cog the Owl's line as your prompt: "Good thinking. Show me the why."

3. 3. Do · 10 min

   Pairs work through the 5 steps on screen or on the printed sheet. Circulate and ask "why?"

4. 4. Discuss · 10 min

   Use two or three of the discussion questions. Ask pairs to share different answers, not just correct ones.

5. 5. Reflect · 5 min

   Exit ticket: one sentence on how they used problem solving today.

Discussion questions

• What was the hardest choice in "Perimeter Park Builder", and why?
• A rectangle is 6 m long and 3 m wide. Its perimeter — explain your reasoning to a partner.
• A square has sides of 4 cm. Its perimeter — explain your reasoning to a partner.
• A 20 m fence has a 2 m gate opening. How much fencing — explain your reasoning to a partner.
• Where could you use problem solving outside school this week?
• If you did this again, what would you change?

Adapting it

Support: Read prompts aloud, pair with a confident partner, and accept spoken or drawn answers for writing steps.

Stretch: Ask pupils to create their own extra step for a partner and explain the correct answer.

Curriculum links

• National Curriculum: Maths: number, calculation, fractions and reasoning (KS1/KS2)
• National Curriculum: Maths: reasoning mathematically and problem solving
• National Curriculum: Computing: logical reasoning and algorithms
• PSHE: Living in the wider world: making decisions and evaluating choices