Lesson Plan

• Write down the midpoint (arc) formulae for price, income and cross‑elasticity of demand.
• Calculate PED, YED and XED from given price, quantity and income data.
• Interpret the sign and magnitude of each elasticity to classify goods (elastic/inelastic, normal/luxury/inferior, substitutes/complements).
• Apply elasticity concepts to short real‑world scenarios and explain their relevance to revenue and welfare.

• Projector and screen
• Whiteboard and markers
• Printed worksheet with practice calculations
• Scientific calculators (or calculator app)
• Formula cheat‑sheet handout

Start with a quick poll: “If the price of your favourite streaming service dropped, would you watch more?” Use this to remind students of how price changes affect quantity demanded. Review the concept of percentage change and the demand curve. State that by the end of the lesson they will be able to compute and interpret three key elasticity measures.

1. Do‑Now (5') – Students calculate a simple percentage change on a slip of paper and submit answers.
2. Mini‑lecture (10') – Introduce the midpoint (arc) formulae for PED, YED and XED, showing one worked example for PED on the board.
3. Guided Practice (15') – Teacher walks through the YED example; students follow on their worksheets, checking steps together.
4. Pair Activity (15') – Students complete XED calculations from a set of real‑world scenarios, then compare answers.
5. Class Discussion (10') – Groups share interpretations (elastic vs inelastic, normal vs inferior, substitutes vs complements) and link to revenue implications.
6. Exit Ticket (5') – Each student writes one correct formula and a brief interpretation of a given elasticity value.

Recap the three formulae and the key interpretation rules. Collect exit tickets to gauge understanding, and assign a homework worksheet that extends the practice with additional price, income and cross‑price scenarios.