IB Computer Science 2027 – B3.2.4 Composition and aggregation – Lesson & Worksheet

Bespoke, fully editable lesson for the new IB Diploma Computer Science syllabus (first assessment 2027): B3.2.4 Composition and aggregation. Slides, worksheet and full answers.

Written for the 2027 IB Computer Science guide, unit B3 Object-oriented programming (HL only). Everything is editable, so you can adapt it to your class.

What’s included

• PowerPoint lesson (12 slides) with speaker notes on every slide
• Student worksheet (Word), ready to print or edit
• Answer sheet (Word) with model answers for every question

B3.2.4 Composition and aggregation

By the end of the lesson students can:

• Explain “has-a” relationships: composition and aggregation
• Write Python classes that show each relationship
• Choose between composition, aggregation and inheritance for a design

Worksheet sections: A. Key ideas; B. Sort them; C. Model a library; D. Spot the relationship; E. Challenge

Every lesson includes

• Learning goals and a starter question
• Clear explanations with worked examples (Python where code is needed)
• A quick check and a “your turn” task linked to the worksheet
• An exit ticket

Format

• PowerPoint (.pptx) and Word (.docx), fully editable
• Works in PowerPoint and Google Slides
• Calm pastel design, consistent across the whole IB course

These are independent resources written for the IB Diploma Programme Computer Science guide (first assessment 2027). They are not produced or endorsed by the International Baccalaureate Organization.