Class: Junior Secondary School 1 (JSS1, JSS 1)
Term: 2nd Term
Week: 7
Age: 12 years
Duration: 45 minutes
Subject: Mathematics
Curriculum Theme: Mathematics
Previous Lesson: Simple Equation in One Variable and Types of Equality
Topic: Directed Numbers
Subject Matter: Addition and subtraction of numbers using number line, Use of number line

Specific Objectives

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

Cognitive Domain:
(a) Identify and differentiate between positive and negative numbers.
(b) Solve problems involving addition and subtraction of directed numbers using a number line.
Affective Domain:
(a) Develop interest and confidence in solving problems with directed numbers.
Psychomotor Domain:
(a) Accurately represent directed numbers on a number line.
(b) Demonstrate addition and subtraction of directed numbers using drawn or practical number lines.
Social Domain:
(a) Cooperate in groups to discuss and solve examples of directed number problems.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum
Lagos State Unified Scheme of work for Junior Secondary Schools
Math is Fun – Directed Number Definition (Illustrated Mathematics Dictionary)
Relevant Textbooks

Instructional Materials

The teacher will teach this lesson with the aid of:

Number line chart
Flashcards with positive and negative numbers
Whiteboard and markers
Counters or bottle tops (for demonstration)
Projector or visual slides (if available)

Rationale for the Lesson

This lesson enables pupils to understand how to perform addition and subtraction of directed numbers correctly using a number line, which is essential for problem solving in algebra and everyday calculations.

Prerequisite/Previous Knowledge

Pupils already know about integers, positive and negative numbers, and can identify them on a number line from previous lessons.

Lesson Content/Board Summary

Directed Numbers

Directed numbers are numbers that have signs to show direction or value, either positive (+) or negative (−). Positive numbers are greater than zero, while negative numbers are less than zero.

Addition of Directed Numbers Using Number Line

To add directed numbers, we move along the number line according to the signs of the numbers.

The following are the basic rules for addition:

When adding a positive number, move to the right on the number line.
When adding a negative number, move to the left on the number line.

Examples:

( +3 + (+2) = +5 )
- Start at +3, move 2 steps to the right.
( +4 + (-3) = +1 )
- Start at +4, move 3 steps to the left.
( -2 + (+5) = +3 )
- Start at -2, move 5 steps to the right.

Subtraction of Directed Numbers Using Number Line

Subtraction of directed numbers can be understood as adding the opposite (additive inverse).
That is, ( a – b = a + (-b) ).

The following are the basic rules for subtraction:

Change the subtraction sign to addition.
Change the sign of the second number to its opposite.
Follow the rules of addition to find the answer.

Examples:

( +6 – (+2) = +4 )
→ ( +6 + (-2) = +4 )
( -3 – (+5) = -8 )
→ ( -3 + (-5) = -8 )
( -2 – (-6) = +4 )
→ ( -2 + (+6) = +4 )

Use of Number Line in Solving Problems

The number line helps to visualize the movement of numbers in both directions (right for positive, left for negative).

Example:
Solve ( -4 + 7 ) using number line.

Start from -4 on the number line.
Move 7 steps to the right.
You land on +3.
Answer: ( -4 + 7 = +3 ).

Teaching Methods/Instructional Techniques:

Discussion, Lecture, Demonstration, Guided Practice, Question and Answer, Group Work, Visual Aids

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 positive and negative numbers from the previous lesson and how they are represented on a number line.
Pupils’ Activity: Pupils respond and mention examples of positive and negative numbers.
Learning Point: Pupils recall basic understanding of integers and number lines.

Step 2: Explanation of Directed Numbers

Time: 10 minutes
Teaching Skill: Explanation
Teacher’s Activity: Teacher explains the meaning of directed numbers and uses a chart to show examples of positive and negative values.
Pupils’ Activity: Pupils observe and identify the signs of different numbers.
Learning Point: Pupils understand the concept of directed numbers and their directions.

Step 3: Addition of Directed Numbers Using Number Line

Time: 10 minutes
Teaching Skill: Demonstration
Teacher’s Activity: Teacher demonstrates addition on a number line using examples such as ( +3 + (+2) ) and ( -2 + (+5) ).
Pupils’ Activity: Pupils follow along and use drawn number lines to solve examples.
Learning Point: Pupils can add directed numbers correctly using a number line.

Step 4: Subtraction of Directed Numbers Using Number Line

Time: 10 minutes
Teaching Skill: Guided Practice
Teacher’s Activity: Teacher explains subtraction as adding the opposite and works through examples such as ( +6 – (+2) ) and ( -2 – (-6) ).
Pupils’ Activity: Pupils solve similar problems individually and in groups.
Learning Point: Pupils can subtract directed numbers by changing subtraction to addition of the opposite.

Step 5: Note-Taking

Time: 5 minutes
Teaching Skill: Explanation
Teacher’s Activity: Teacher writes or dictates the lesson summary for pupils to copy.
Pupils’ Activity: Pupils write notes neatly in their exercise books.
Learning Point: Pupils have complete notes for study and revision.

Step 6: Evaluation/Review

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

What are directed numbers?
State two rules for adding directed numbers.
Solve ( -3 + (+6) ).
Solve ( +5 – (-3) ).
Explain how the number line helps in solving directed numbers.
Pupils’ Activity: Pupils respond orally and solve on the board.
Learning Point: Pupils demonstrate understanding of addition and subtraction of directed numbers.

Step 7: Conclusion

Time: 2 minutes
Teaching Skill: Reinforcement
Teacher’s Activity: Teacher summarizes the main points and encourages regular practice.
Pupils’ Activity: Pupils listen and ask questions for clarity.
Learning Point: Pupils understand the importance of correct sign operation and visualization using number lines.

Home Task: Solve three new exercises on Directed Numbers. Show each step and check each answer.

Lesson Keywords

Directed Numbers – numbers with a positive or negative sign
Integer – whole number that can be positive, negative, or zero
Additive Inverse – opposite of a number that sums to zero
Number Line – a line used to represent numbers in order
Operation – a mathematical process such as addition or subtraction

Differentiation

Teacher provides simplified number lines for slower learners while advanced learners solve problems without visual aids. Group work supports peer tutoring.

Note for teachers using this lesson plan

Ensure pupils clearly understand movement on the number line—right for addition of positive and left for subtraction or negative addition. Reinforce with practical demonstrations.