Module 1 · Lesson 2
Lesson 2 · Decomposition
Breaking large problems into parts small enough to actually start on.
Decomposition is the component students take to most quickly and teachers underestimate most often. The skill is not simply "make a list" — it is producing parts that are independent, actionable, and complete when reassembled.
Learning objectives
- Decompose a multi-step task into independent, actionable sub-tasks
- Judge whether a sub-task is small enough to begin
- Spot overlapping or missing parts in a decomposition
- Facilitate a decomposition activity with students
Three tests for a good decomposition
- Can each part be started without waiting on another part? If not, the parts are tangled.
- Is each part small enough that a student knows what to do first? If not, decompose again.
- If every part is completed, is the whole problem solved? If not, something is missing.
Lesson resources
- Decomposition — interactive lesson Walkthrough of decomposition with worked classroom examples. Genially Open
- Decomposition activity sheet Google Docs Open
- Classroom planning template Google Docs Open
- Reflection worksheet Google Docs Open
- Decomposition skills in classroom projects Check-for-understanding quiz. Kahoot Open