Class: Primary 1
Term: 3rd Term
Week: 4
Age: 6 years
Duration: 45 minutes
Subject: Mathematics
Curriculum Theme: Numbers and Numeration
Previous Lesson: 3, Dimensional Shapes, Identification of Cubes, Cuboid, Cylinder, Sphere.
Topic: Subtraction on Number Line
Subject Matter: Reading positive and negative numbers on the number line, 0 inclusive, Concept of subtraction on a number line

Specific Objectives

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

Cognitive Domain:

Identify positive numbers, negative numbers, and zero on a number line.
Define subtraction.
Perform simple subtraction using a number line.

Affective Domain:

Appreciate the use of number lines for basic arithmetic.
Show enthusiasm in participating in number line activities.

Psychomotor Domain:

Draw a simple number line with positive and negative numbers.
Accurately move left on the number line to perform subtraction.

Collaborate with peers during group activities involving number lines.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum
State Unified Scheme of Work
New General Mathematics for Primary Schools 1

Instructional Materials

The teacher will teach this lesson with the aid of:

A large number line chart (showing positive and negative numbers, including zero)
Chalk and chalkboard
Markers

Rationale for the Lesson

This lesson helps pupils to visualize numbers and understand the concept of subtraction in a concrete way. It builds a foundational understanding of number relationships and prepares them for more complex mathematical operations.

Prerequisite/Previous Knowledge

Pupils can count numbers, identify basic numbers, and have a general idea of addition and subtraction.

Lesson Content/Board Summary

Subtraction on Number Line

Reading Positive and Negative Numbers on the Number Line, 0 Inclusive

A number line is a straight line where numbers are placed at equal intervals. Zero (0) is in the middle.

Positive numbers: These are numbers greater than zero. They are found to the right of zero on the number line (e.g., 1, 2, 3, 4…).
Negative numbers: These are numbers less than zero. They are found to the left of zero on the number line (e.g., -1, -2, -3, -4…).
Zero (0): This is the number in the middle, separating positive and negative numbers. It is neither positive nor negative.

Concept of Subtraction on a Number Line

Subtraction means taking away a number from another number. On a number line, when we subtract, we move to the left.

Worked Examples:

Example 1: Subtract 2 from 5 (5 – 2)

Step 1: Draw a number line from 0 to 10.

Step 2: Start at the number 5 on the number line.

Step 3: Move 2 steps to the left (because we are subtracting 2).

Step 4: You will land on the number 3. So, 5 – 2 = 3.

(Teacher will draw a number line on the board showing the steps)

Example 2: Calculate 7 – 3 using a number line

Step 1: Draw a number line.

Step 2: Start at the number 7.

Step 3: Move 3 steps to the left.

Step 4: You will land on the number 4. So, 7 – 3 = 4.

(Teacher will draw a number line on the board showing the steps)

Teaching Methods/Instructional Techniques

Discussion, Lecture, Demonstration, Question and Answer, Visual Aids

Instructional Procedures

Step 1: Introduction

Time: 5 minutes
Teaching Skill: Set Induction
Teacher’s Activity: The teacher greets the pupils and asks them to recall what they know about counting and simple subtraction. The teacher then introduces the idea of using a line to help with subtraction.
Pupils’ Activity: Pupils respond to greetings and share their previous knowledge about numbers.
Learning Point: Pupils are reminded of previous knowledge and prepared for the new topic.

Step 2: Introducing the Number Line

Time: 8 minutes
Teaching Skill: Explanation/Demonstration
Teacher’s Activity: The teacher displays a number line chart and explains what it is. The teacher points out zero, positive numbers to the right, and negative numbers to the left.
Pupils’ Activity: Pupils observe the number line chart and listen to the teacher’s explanation. They identify zero, positive, and negative numbers.
Learning Point: Pupils understand the structure of a number line and the positions of different types of numbers.

Step 3: Reading Numbers on the Number Line

Time: 8 minutes
Teaching Skill: Questioning/Practice
Teacher’s Activity: The teacher points to various numbers on the number line chart (positive and negative) and asks pupils to read them aloud. The teacher ensures pupils understand that negative numbers are less than zero.
Pupils’ Activity: Pupils take turns reading the numbers pointed to by the teacher.
Learning Point: Pupils practice reading and identifying numbers on a number line.

Step 4: Concept of Subtraction on a Number Line

Time: 8 minutes
Teaching Skill: Explanation/Demonstration
Teacher’s Activity: The teacher defines subtraction and explains that when subtracting on a number line, one must move steps to the left. The teacher demonstrates with a simple example like 3 – 1.
Pupils’ Activity: Pupils listen attentively and observe the teacher’s demonstration.
Learning Point: Pupils understand that subtraction on a number line involves moving to the left.

Step 5: Worked Examples

Time: 8 minutes
Teaching Skill: Demonstration/Guided Practice
Teacher’s Activity: The teacher writes and solves the examples from the board summary (5 – 2 and 7 – 3) step-by-step on the chalkboard, drawing the number lines clearly. The teacher encourages pupils to follow along.
Pupils’ Activity: Pupils copy the examples into their notebooks and ask questions for clarification.
Learning Point: Pupils learn how to apply the number line method to solve subtraction problems.

Step 6: Class Activity

Time: 8 minutes
Teaching Skill: Group Work/Monitoring
Teacher’s Activity: The teacher gives pupils simple subtraction problems (e.g., 4 – 2, 6 – 3, 8 – 5) to solve in pairs using number lines in their exercise books. The teacher moves around to provide assistance.
Pupils’ Activity: Pupils work in pairs to solve the given subtraction problems using number lines.
Learning Point: Pupils practice and consolidate their understanding of subtraction on a number line.

Step 7: Evaluation/Review

Time: 5 minutes
Teaching Skill: Questioning/Assessment
Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

What is a number line?
Where do we find positive numbers on a number line?
Where do we find negative numbers on a number line?
Show how to calculate 6 – 4 using a number line.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 3 minutes
Teaching Skill: Summarization
Teacher’s Activity: The teacher summarizes the lesson by reiterating that a number line helps us to understand numbers and perform subtraction by moving to the left. The teacher assigns homework.
Pupils’ Activity: Pupils listen to the summary and copy the assigned homework.
Learning Point: Pupils recall the main points of the lesson and are given further practice.

Home Task: Solve two new exercises on Subtraction on Number Line. Show each step and check each answer.

Lesson Keywords

Number Line – A straight line where numbers are placed at equal intervals.
Positive Numbers – Numbers greater than zero, found to the right of zero.
Negative Numbers – Numbers less than zero, found to the left of zero.
Zero (0) – The number in the middle of a number line, neither positive nor negative.
Subtraction – Taking away a number from another number, moving left on a number line.

Differentiation

For pupils who are struggling, the teacher will provide more one-on-one guidance and use a physical, manipulable number line to demonstrate the movements. For advanced pupils, the teacher can introduce slightly larger numbers or challenge them with simple word problems that require subtraction on a number line.

Note for teachers using this lesson plan

Ensure the number line drawn on the board is clear, well-spaced, and properly labeled. Encourage pupils to draw their own number lines neatly in their notebooks. Emphasize the direction of movement for subtraction (always to the left). Use varied examples to cater to different learning styles.