Lesson Plan

• Describe the binary number system and its positional values.
• Apply the division‑by‑2 method to convert positive decimal numbers to binary.
• Apply the largest‑power method to convert positive decimal numbers to binary.
• Convert positive binary numbers to decimal using positional multiplication.
• Check conversions for accuracy and identify common errors.

• Projector or interactive whiteboard
• Printed worksheets with conversion exercises
• Calculators (optional)
• Handout summarising the two conversion methods
• Markers and whiteboard
• Exit‑ticket slips

Start with the question “What base does a computer use to store data?” to activate prior knowledge of binary. Briefly recap that each binary position represents a power of 2. Explain that today students will master two reliable methods for converting between decimal and binary and will learn how to verify their answers. Success will be measured by accurate conversions in both directions and the ability to spot typical mistakes.

1. Do‑now (5 minutes): Students list the powers of 2 up to 128 and convert a simple number mentally.
2. Mini‑lecture (10 minutes): Demonstrate the division‑by‑2 method with a sample number, highlighting the bottom‑up reading of remainders.
3. Guided practice (10 minutes): In pairs, students convert 73₁₀ to binary using the division method while the teacher circulates.
4. Introduce the largest‑power method (8 minutes): Show the step‑by‑step process and have students try converting 156₁₀.
5. Binary‑to‑decimal conversion (7 minutes): Walk through the positional multiplication method with 101101₂, then students complete a worksheet.
6. Common pitfalls quiz (5 minutes): Quick whole‑class check on counting powers from 2⁰ and reverse‑checking answers.
7. Exit ticket (5 minutes): Each student writes one decimal‑to‑binary and one binary‑to‑decimal conversion of their choice.

Recap the two decimal‑to‑binary methods and the binary‑to‑decimal calculation, emphasizing the importance of checking work by converting back. Collect exit tickets to gauge understanding. For homework, assign three additional conversion problems (two each way) and ask students to note any mistakes they discover during the reverse check.