Success criteria
- I can state the question and plan before calculating.
- I can label information as needed or unnecessary.
- I can critique an answer using estimation and context.
Explain
Route A has 8 stops at HK$3.75 per stop, a HK$12 fixed fee, and a HK$5 coupon. Route B has 6 stops at HK$4.50 plus a HK$9 fee. A driver’s favourite colour is blue. Explain why the colour is unnecessary and why the coupon must be subtracted only once.
Independent practice
What is Route A's total cost?
What is Route B's total cost?
How much more does Route A cost than Route B?
A solver says Route A costs HK$370. What is the strongest first critique?
Estimate the size from the quantities and costs before recomputing.
Transfer — offline route decision
Create two workable delivery or event-budget options using paper. Include one distracting fact. Ask another person to choose the cheaper valid option and defend the operation sequence.
Delayed check
One week later, solve an unfamiliar two-option budget problem. Before calculating, circle the question, cross out unnecessary information, and write an estimate range.
Evidence and next step
Save the independently solved transfer problem at jeremy/portfolio/math/unit-2/route-decision.md.
- Correct choice + defensible sequence + plausible estimate → continue.
- Calculation correct but plan unclear → practise annotating one problem.
- Wrong operation choice → use units and the question to rebuild the plan.