Teacher guide · Think Lab · Harder · about 35 min
🛡️ Guardians of Numberfall
Pupils practise problem solving through "Guardians of Numberfall": The number kingdom is falling. Beat each guardian with maths.
Lesson guide
1. Hook · 5 min
Show the 🛡️ mission title and read the opening: "The Gate Guardian asks: 6 × 7 = ?". Take three quick guesses.
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. Do · 10 min
Pairs work through the 7 steps on screen or on the printed sheet. Circulate and ask "why?"
4. Discuss · 10 min
Use two or three of the discussion questions. Ask pairs to share different answers, not just correct ones.
5. Reflect · 5 min
Exit ticket: one sentence on how they used problem solving today.
Discussion questions
- What was the hardest choice in "Guardians of Numberfall", and why?
- The Gate Guardian asks: 6 × 7 = — explain your reasoning to a partner.
- The Bridge Guardian: what is 3/4 of 20 — explain your reasoning to a partner.
- The Time Guardian: a film starts at 14:45 and lasts 95 minutes. When does it end — 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: reasoning mathematically and problem solving
- National Curriculum: Computing: logical reasoning and algorithms
- PSHE: Living in the wider world: making decisions and evaluating choices
Pupil sheet
🛡️ Guardians of Numberfall
Name: ____________________ Date: __________
1. The Gate Guardian asks: 6 × 7 = ?
☐ 42
☐ 36
☐ 48
2. The Bridge Guardian: what is 3/4 of 20?
☐ 12
☐ 15
☐ 16
3. Cross the stones — smallest to largest.
___ 0.4
___ 0.75
___ 1.2
___ 1/2
___ 4/5
4. The Shape Guardian: match shape to fact.
Triangle → ________________
Square → ________________
Circle → ________________
Cube → ________________
5. The Time Guardian: a film starts at 14:45 and lasts 95 minutes. When does it end?
☐ 16:20
☐ 16:00
☐ 15:40
6. Final guardian: spend up to 30 crystals on defences (at least 3).
Budget: £30
☐ Wall — £10
☐ Watchtower — £8
☐ Bridge trap — £6
☐ Lanterns — £4
☐ Scouts — £7
☐ Dragon (risky) — £15
Total spent: £______
7. Explain the maths behind your defence choices.