| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Additional Mathematics |
| Lesson Topic: Know and use the laws of logarithms, including change of base, and express combinations of logarithms as a single logarithm |
Learning Objective/s:
- Apply the product, quotient, and power laws to simplify logarithmic expressions.
- Use the change‑of‑base formula to evaluate logarithms with any base on a calculator.
- Convert a combination of logarithmic terms into a single logarithm.
- Solve exponential and logarithmic equations using properties of logs.
- Explain the inverse relationship between exponential and logarithmic functions.
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Materials Needed:
- Projector or interactive whiteboard
- Teacher’s slide deck on logarithm laws
- Student worksheets with practice problems
- Scientific calculators (or calculator app)
- Graph paper
- Whiteboard markers
- Handout of the change‑of‑base formula
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Introduction:
Begin with a quick real‑world hook: ask students how they would compare the growth of two investments with different interest rates. Review that exponential and logarithmic functions are inverses and recall the basic definitions. State that by the end of the lesson they will be able to manipulate logarithms using the laws and evaluate any log with a calculator.
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Lesson Structure:
- Do‑now (5'): Students solve a simple exponential equation on the board to activate prior knowledge.
- Mini‑lecture (10'): Present the six logarithm laws and the change‑of‑base formula with examples using the projector.
- Guided practice (12'): Work through the example 3log₅x + ½log₅y – log₅z, prompting students to apply each law step‑by‑step.
- Calculator activity (8'): Students use calculators to evaluate logs of non‑standard bases via the change‑of‑base formula, checking answers with peers.
- Independent practice (10'): Worksheet with mixed problems (simplify logs, solve equations, change of base) while the teacher circulates.
- Quick check (5'): Exit ticket – write one law of logs and an example of its use.
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Conclusion:
Summarise how the laws allow us to rewrite complex logarithmic expressions as a single log and how the change‑of‑base formula extends our calculator capabilities. Collect the exit tickets as a retrieval check and assign additional worksheet problems for homework, encouraging students to practice both simplifications and solving equations.
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