Class: Junior Secondary School 2 (JSS2, JSS 2)
Term: 2nd Term
Week: 9
Age: 13 years
Duration: 45 minutes
Subject: Mathematics
Curriculum Theme: Mathematics
Previous Lesson: Scale Drawing, Conversion, Calculations and Composite Designs
Topic: Graphs
subject Matter: Revision of plotting of points on the Cartesian plane, solutions of linear equations in two variables using graphs, Linear graphs from real life situations.

Specific Objectives

By the end of the lesson, pupils should be able to:

Cognitive Domain:
(a) Revise and accurately plot points on the Cartesian plane.
(b) Solve linear equations in two variables using graphs.
(c) Interpret and construct linear graphs from real-life situations.
Affective Domain:
(a) Value accuracy and neatness in plotting graphs.
(b) Appreciate the importance of graphs in representing data.
Psychomotor Domain:
(a) Plot points and draw lines on graph paper with precision.
(b) Construct graphs from given equations and real-life data.
Social Domain:
(a) Work collaboratively in pairs or groups to solve graph-related problems.

Reference Materials

The following resources was used in planning this lesson:

9 Years Basic Education Curriculum
Lagos State Unified Scheme of work for Junior Secondary Schools
BBC – How to plot a linear equation graph
Relevant Textbooks

Instructional Materials

The teacher will teach this lesson with the aid of:

Graph papers and rulers
Marker pens and whiteboard
Chart showing Cartesian plane and examples
Visual aids illustrating real-life linear relationships
Projector or slides with solved graph examples

Rationale for the Lesson

This lesson enables pupils to revise plotting points, solve linear equations graphically, and connect mathematics to real-life situations using graphs.

Prerequisite/Previous Knowledge

Pupils should already know the concept of Cartesian coordinates, plotting points, and solving simple linear equations in two variables.

Lesson Content/Board Summary

Graphs

Graphs are visual representations of data or mathematical relationships, allowing easier analysis and interpretation.

Revision of Plotting Points on the Cartesian Plane

The Cartesian plane is a two-dimensional plane with a horizontal axis (x-axis) and vertical axis (y-axis) intersecting at the origin (0,0). Points are plotted using ordered pairs (x, y).

The following are steps for plotting points:

Identify the x-coordinate and y-coordinate from the ordered pair.
Move along the x-axis to the x-coordinate.
Move parallel to the y-axis to reach the y-coordinate.
Mark the point clearly on the plane.
Repeat for all points required.

Example: Plot the points A(2,3) and B(-1,4) on the Cartesian plane.

Solutions of Linear Equations in Two Variables Using Graphs

Linear equations in two variables can be represented as straight lines on the Cartesian plane. The point where the line passes through coordinates represents a solution of the equation.

The following are steps for solving linear equations graphically:

Rewrite the equation in the form y = mx + c, if necessary.
Choose at least two values of x and calculate corresponding y values.
Plot the points (x, y) on the Cartesian plane.
Join the points with a straight line.
Any point on the line is a solution of the equation.

Example: Solve y = 2x + 1 graphically using x = 0, 1, 2.

If x = 0, y = 1 → Plot (0,1)
If x = 1, y = 3 → Plot (1,3)
If x = 2, y = 5 → Plot (2,5)
Draw a straight line through the points to represent the solution.

Linear Graphs from Real-Life Situations

Linear graphs can represent relationships such as speed vs. time, cost vs. quantity, or distance vs. time.

The following are examples of real-life linear graphs:

A taxi charges N500 per kilometer: Total cost (y) = 500 × number of km (x).
A shop sells pencils at N50 each: Total cost (y) = 50 × number of pencils (x).
Water consumption: y = 10x, where y is liters of water for x number of days.

These graphs help to visualize relationships and make predictions.

Teaching Methods/Instructional Techniques:

Discussion, Lecture, Explanation, Demonstration, Visual Aids, Group Work, Question and Answer

Instructional Procedures

To deliver this lesson, the teacher will adopt the following steps:

Step 1: Introduction

Time: 5 minutes
Teaching Skill: Set Induction
Teacher’s Activity: Teacher asks pupils to recall previous lessons on plotting points and equations and relates it to real-life examples.
Pupils’ Activity: Pupils respond by recalling points and equations.
Learning Point: Pupils are prepared for revision and practical application of graphs.

Step 2: Revision of Plotting Points

Time: 10 minutes
Teaching Skill: Explanation
Teacher’s Activity: Teacher reviews plotting points on the Cartesian plane using examples on the board.
Pupils’ Activity: Pupils plot points on graph paper as instructed.
Learning Point: Pupils refresh knowledge and practice plotting points accurately.

Step 3: Solving Linear Equations Using Graphs

Time: 10 minutes
Teaching Skill: Demonstration
Teacher’s Activity: Teacher demonstrates solving linear equations graphically and shows workings step by step.
Pupils’ Activity: Pupils solve given equations on graph paper.
Learning Point: Pupils understand how to represent linear equations visually.

Step 4: Linear Graphs from Real-Life Situations

Time: 10 minutes
Teaching Skill: Explanation/Discussion
Teacher’s Activity: Teacher provides real-life scenarios and guides pupils to construct corresponding linear graphs.
Pupils’ Activity: Pupils work in pairs to plot graphs from real-life data.
Learning Point: Pupils apply mathematical concepts to practical situations.

Step 5: Note-Taking

Time: 5 minutes
Teaching Skill: Explanation
Teacher’s Activity: Teacher writes key points and examples on the board for pupils to copy.
Pupils’ Activity: Pupils take organized notes in their exercise books.
Learning Point: Pupils have reference material for future revision.

Step 6: Evaluation/Review

Time: 3 minutes
Teaching Skill: Questioning
Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

Plot the points (2,3) and (-2,4) on the Cartesian plane.
Solve y = x + 2 graphically using x = 0,1,2.
Give an example of a real-life situation that can be represented by a linear graph.
Pupils’ Activity: Pupils answer questions and present their graphs.
Learning Point: Pupils demonstrate understanding of objectives.

Step 7: Conclusion

Time: 2 minutes
Teaching Skill: Reinforcement
Teacher’s Activity: Teacher summarizes the lesson, highlights key points, and encourages pupils to practice plotting and interpreting graphs.
Pupils’ Activity: Pupils listen and ask clarifying questions.
Learning Point: Pupils consolidate learning and recognize practical applications of graphs.

Lesson Keywords

Cartesian Plane – A coordinate plane with x and y axes
Linear Equation – An equation of the first degree with two variables
Graph – Visual representation of data or relationships
Coordinate – An ordered pair (x, y) used to locate a point
Slope – The steepness of a line in a graph

Differentiation

Teacher supports slow learners with step-by-step plotting guidance while advanced learners are encouraged to create additional graphs from real-life scenarios.

Note for teachers using this lesson plan

Ensure graph papers are correctly oriented and axes labeled. Encourage pupils to check calculations before plotting and review accuracy of lines drawn.