Lesson Plan

• Describe Boolean operators and their representation in logic gates.
• Construct accurate truth tables for half‑adder and full‑adder circuits.
• Apply a step‑by‑step method to derive sum and carry outputs for combinational adders.
• Analyse how truth tables support the design of larger arithmetic units.

• Projector or interactive whiteboard
• Printed worksheets with half‑adder and full‑adder tables
• Logic‑gate symbols handout
• Digital logic simulation software (e.g., Logisim)
• Whiteboard markers and erasers
• Calculator (optional)

Begin with a quick puzzle that asks students to predict the output of simple AND, OR and XOR gates. Review the Boolean operators they already know and link this to the idea of combinational circuits. Explain that by the end of the lesson they will be able to produce complete truth tables for half‑adders and full‑adders.

1. Do‑now (5'): Recall Boolean operators and fill a short table of AND, OR, NOT, XOR results.
2. Mini‑lecture (10'): Introduce the half‑adder, show its XOR (sum) and AND (carry) gates, and display the truth table.
3. Guided practice (10'): In pairs, students complete a half‑adder worksheet and compare answers.
4. Mini‑lecture (10'): Explain the full‑adder construction using two half‑adders and an OR gate; present the sum and carry formulas.
5. Group activity (15'): Students follow a step‑by‑step procedure to build the full‑adder truth table, recording intermediate XOR results and carry terms.
6. Check for understanding (5'): Exit ticket – write the Boolean expressions for Sum and Carry‑out of a full‑adder and list one real‑world application.

Recap how systematic truth‑table construction reveals the behaviour of half‑adders and full‑adders. Collect the exit tickets to gauge mastery and address any lingering misconceptions. Assign homework: create a truth table for a 4‑bit ripple‑carry adder and calculate the total gate count.