AvailableSecondary mathematics
Square photograph
Expansion of the square of a difference
Overview
A square photograph is printed on a square sheet of paper. As the photograph becomes smaller than the page, students investigate how the area changes and discover the algebraic structure represented by (a − b)². Through visual decomposition and area reasoning, learners construct the identity rather than memorise it.
Key ideas
- Area models
- Algebraic representation
- Visual reasoning
- Expansion of expressions
How this lesson is built
This lesson follows the MSS learning flow: situation, observation, exploration, representation, formalisation, and application.
Read the full learning flowResources
- Lesson designReady
- Teacher guideReady
- Student activitiesReady
- Assessment ideasReady
Lesson video
Lesson video coming soon.