## Lesson Plan: Changing the Subject of a Formula
**Grade Level**: Junior Secondary 3
**Subject**: Mathematics
**Duration**: 60 minutes
**Topic**: Changing the Subject of a Formula
**Objectives**:
By the end of this lesson, students should be able to:
1. Understand what it means to change the subject of a formula.
2. Apply algebraic techniques to rearrange formulas.
3. Successfully change the subject of given formulas.
**Materials**:
- Whiteboard and markers
- Textbook/handout with practice problems
- Worksheets for in-class practice
- Calculator (optional)
**Lesson Outline**:
### Introduction (10 minutes)
1. **Greeting and Attendance** (2 minutes)
2. **Introduction to the Topic** (3 minutes)
- Begin by asking students if they have ever rearranged a formula in Science or Mathematics.
- Explain that today's lesson will focus on changing the subject of a formula, which means solving for a different variable in an equation.
3. **Learning Objectives** (2 minutes)
- Highlight the objectives of the lesson.
4. **Importance of Changing the Subject** (3 minutes)
- Discuss real-life examples where changing the subject of a formula is useful, such as physics formulas (e.g., rearranging \( v = u + at \) to solve for \( a \)).
### Direct Instruction (15 minutes)
1. **Review Basic Algebraic Techniques** (5 minutes)
- Briefly review solving equations, including addition, subtraction, multiplication, division, and working with fractions.
2. **Explain the Process of Changing the Subject** (10 minutes)
- Provide a step-by-step method for changing the subject:
1. Identify the variable you want to solve for.
2. Use inverse operations to isolate that variable on one side of the equation.
3. Apply the same operations to both sides of the equation to maintain balance.
- Work through a simple example on the board:
- Example: Change the subject of the formula \( A = \frac{1}{2}bh \) to \( h \).
- Original formula: \( A = \frac{1}{2}bh \)
- Multiply both sides by 2: \( 2A = bh \)
- Divide both sides by \( b \): \( h = \frac{2A}{b} \)
### Guided Practice (20 minutes)
1. **Class Exercises on the Board** (10 minutes)
- Work through several examples as a class, changing the subject of various formulas. Include both linear and non-linear equations.
- Example 1: \( P = 4s \), change to \( s \).
- Solution: \( s = \frac{P}{4} \)
- Example 2: \( C = 2\pi r \), change to \( r \).
- Solution: \( r = \frac{C}{2\pi} \)
- Example 3: \( y = mx + b \), change to \( x \).
- Solution: \( x = \frac{y - b}{m} \)
2. **Small Group/Pair Work** (10 minutes)
- Hand out worksheets with practice problems.
- Allow students to work in pairs or small groups to solve the problems, providing support as needed.
- Circulate around the room to assist and monitor progress.
### Independent Practice (10 minutes)
1. **Worksheet Completion** (10 minutes)
- Assign several additional problems for students to complete individually.
- Encourage students to try changing the subject for both the easy and challenging formulas. Support students that may need extra help.
### Conclusion (5 minutes)
1. **Review and Reflect** (3 minutes)
- Review some of the problems from the worksheet and their solutions. Discuss common errors and the correct methods.
2. **Recap Learning** (1 minute)
- Summarize what was learned and emphasize the importance of each step in changing the subject of a formula.
3. **Homework Assignment** (1 minute)
- Assign a set of homework problems for additional practice.
**Assessment**:
- Formative: Monitor student participation during class exercises and guided practice.
- Summative: Review and grade the worksheet and homework assignments to assess student understanding.
**Differentiation**:
- Provide additional support and examples for students who struggle with algebraic manipulations.
- Challenge advanced students with more complex formulas involving multiple steps or exponents.
**Closure**:
- Thank the students for their participation.
- Remind them to practice consistently as proficiency in these techniques is crucial for their success in higher-level math courses.