Lesson Plan

• Describe situations where BCD is preferred over binary for exact decimal representation.
• Explain why hexadecimal is used for memory addresses, debugging, and colour codes.
• Compare the advantages and limitations of BCD and hexadecimal in real‑world systems.
• Apply conversion techniques to translate decimal time to BCD and manipulate hex literals in code.

• Projector or interactive whiteboard
• Slide deck showing BCD and hexadecimal examples
• Worksheet with conversion exercises
• Sample C/assembly code snippets for hex literals
• Calculator or digital‑clock simulation
• Printed handout of the BCD vs. Hex comparison table

Begin with a quick poll: Who has seen a digital clock or a colour code like #FF7F00? Review that binary underlies all data, but different encodings serve specific purposes. Today students will identify where BCD and hexadecimal are applied and how to convert between decimal, BCD, and hex, meeting the success criteria of explaining and demonstrating these uses.

1. Do‑now (5’) – Students list everyday devices that display numbers (e.g., clocks, receipts); teacher records responses.
2. Mini‑lecture (10’) – Explain BCD concept and key applications using slides and a diagram.
3. Guided conversion activity (10’) – Work through the decimal‑to‑BCD example (14:35) on the board; students complete a worksheet.
4. Hexadecimal overview (10’) – Demonstrate hex for memory addresses, colour codes, and debugging with a short code snippet.
5. Hands‑on coding task (15’) – In small groups, students write/modify a C fragment to set a register using hex masks and convert a given decimal to hex.
6. Check for understanding (5’) – Exit‑ticket: one sentence describing a scenario where BCD is preferred and another where hex is preferred.

Summarise that BCD ensures exact decimal values in finance and time‑keeping, while hex provides a compact, engineer‑friendly representation for addresses and data. Ask pupils to write an exit‑ticket stating one practical use of each format. For homework, assign a short problem set converting between decimal, BCD, and hex and analysing a real‑world protocol example.