Lesson Plan

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Lesson Plan
Grade: Date: 17/01/2026
Subject: Computer Science
Lesson Topic: Understand the concept of overflow and why it occurs in binary addition
Learning Objective/s:
  • Describe what overflow means in binary addition.
  • Explain why overflow occurs for unsigned and two’s‑complement representations.
  • Perform binary addition and identify overflow using carry bits.
  • Apply overflow detection rules to solve practice problems.
Materials Needed:
  • Projector or interactive whiteboard
  • Slide deck illustrating binary addition and overflow
  • Worksheets with practice questions
  • Calculators (binary mode) or computers with an IDE
  • Whiteboard and markers
  • Handouts of overflow detection rules
 Introduction:
Begin with a quick mental‑math challenge: ask students what happens when you add 200 and 100 on a calculator that only shows eight digits. Connect this to their prior learning of binary numbers and fixed‑size registers, and tell them they will learn how computers detect and handle the resulting overflow. Success will be measured by correctly predicting the stored result of an 8‑bit addition.
Lesson Structure:
  1. Do‑Now (5'): Students solve a short binary addition on sticky notes and note any extra carry.
  2. Mini‑lecture (10'): Explain overflow, unsigned vs signed ranges, using slides.
  3. Guided demonstration (12'): Model the 8‑bit addition of 200 + 100 and show the discarded carry.
  4. Interactive activity (15'): Pairs work on worksheet problems, using calculators to check overflow detection.
  5. Check for understanding (8'): Quick quiz (Kahoot or show of hands) on overflow rules.
  6. Summary & reflection (5'): Review key rules and answer remaining questions.
Conclusion:
Recap the definition of overflow and the two detection methods for unsigned and two’s‑complement numbers. Have students write one exit‑ticket sentence describing how they would know overflow occurred in a given addition. Assign homework to create their own binary addition examples that illustrate overflow.