Class: Primary 4 (Pry 4)
Term: 1st Term
Week: 3
Age: 9 years
Duration: 45 minutes
Subject: General Mathematics
Curriculum Theme: Numbers and Numeration
Previous Lesson: Whole Numbers, Roman Numerals, Ordering and Place Value.
Topic: L. C. M
Subject Matter: LCM of two numbers up to 60, finding LCM using multiples method, finding LCM using factor method steps, practice problems on LCM.

Specific Objectives

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

Cognitive Domain:

Define Least Common Multiple (LCM).
Find the LCM of two numbers using the multiples method.
Find the LCM of two numbers using the prime factorization (factor) method.

Affective Domain:

Appreciate the importance of LCM in solving real-life problems.
Participate actively in class discussions and problem-solving.

Psychomotor Domain:

Accurately calculate the LCM of given numbers up to 60.
Apply the steps of the factor method to find LCM.

Work collaboratively with peers to solve LCM problems.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum (Primary 4 Mathematics)
State Unified Scheme of Work for Primary 4 Mathematics
Essential Mathematics for Primary Schools, Book 4
https://www.example.com/lcm-for-primary-4
https://www.youtube.com/watch?v=lcm_explanation

Instructional Materials

The teacher will teach this lesson with the aid of:

Mathematics textbook for Primary 4
Whiteboard/Chalkboard and markers/chalk
Chart showing multiples of various numbers
Flashcards with numbers

Rationale for the Lesson

Understanding LCM helps pupils to solve problems involving common events or quantities, such as finding when two events will happen again at the same time. This concept is important for later topics in fractions and other areas of mathematics.

Prerequisite/Previous Knowledge

Pupils should have prior knowledge of multiples of numbers, factors, prime numbers, and basic multiplication tables.

Lesson Content/Board Summary

L. C. M (Least Common Multiple)

Definition of LCM

The Least Common Multiple (LCM) of two or more numbers is the smallest non-zero common multiple of those numbers. It is the smallest number that is a multiple of all the given numbers.

Finding LCM Using Multiples Method

To find the LCM of two numbers using the multiples method, follow these steps:

List the multiples of the first number.
List the multiples of the second number.
Identify the common multiples (numbers that appear in both lists).
The smallest of these common multiples is the LCM.

Example: Find the LCM of 4 and 6.

Multiples of 4: 4, 8, 12, 16, 20, 24, …
Multiples of 6: 6, 12, 18, 24, 30, …
Common multiples: 12, 24, …
The smallest common multiple is 12. So, LCM (4, 6) = 12.

Finding LCM Using Prime Factorization Method (Factor Method)

To find the LCM of two numbers using the prime factorization method, follow these steps:

Find the prime factors of each number.
Write each number as a product of its prime factors in index form (if applicable).
For each distinct prime factor, take the highest power that appears in any of the factorizations.
Multiply these highest powers together to get the LCM.

Example: Find the LCM of 12 and 18.

Prime factors of 12: 2 x 2 x 3 = 2² x 3¹
Prime factors of 18: 2 x 3 x 3 = 2¹ x 3²
Highest power of 2 is 2².
Highest power of 3 is 3².
LCM = 2² x 3² = 4 x 9 = 36.

Practice Problems on LCM

Pupils will solve various problems to reinforce their understanding of finding LCM using both methods for numbers up to 60.

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 reviews the concept of multiples by asking pupils to state multiples of 2, 3, and 5. The teacher then introduces the topic, L.C.M., by explaining that today’s lesson will focus on finding the smallest common multiple.
Pupils’ Activity: Pupils respond to the teacher’s questions about multiples and listen attentively to the introduction.
Learning Point: Pupils recall multiples and are prepared for the new topic.

Step 2: Explanation of LCM

Time: 7 minutes
Teaching Skill: Explanation/Definition
Teacher’s Activity: The teacher defines LCM as the Least Common Multiple and explains its meaning using simple language and a basic example, like finding the first number that is a multiple of both 2 and 3. The teacher writes the definition on the board.
Pupils’ Activity: Pupils listen, take notes, and ask questions for clarification.
Learning Point: Pupils understand the definition of LCM.

Step 3: Finding LCM Using Multiples Method

Time: 10 minutes
Teaching Skill: Demonstration/Guided Practice
Teacher’s Activity: The teacher demonstrates how to find the LCM of two numbers (e.g., 8 and 12) using the multiples method. The teacher writes out the multiples of each number and identifies the common multiples, then selects the least. The teacher gives another example for pupils to try.
Pupils’ Activity: Pupils observe the demonstration, follow along, and then attempt to solve the given practice problem.
Learning Point: Pupils learn how to find LCM by listing multiples.

Step 4: Introduction to Prime Factorization Method

Time: 8 minutes
Teaching Skill: Explanation/Introduction
Teacher’s Activity: The teacher briefly reminds pupils about prime factors. The teacher then introduces the prime factorization method as another way to find LCM, explaining that it is useful for larger numbers. The teacher outlines the steps on the board.
Pupils’ Activity: Pupils recall prime factors and listen to the introduction of the new method, noting the steps.
Learning Point: Pupils understand that there is an alternative method for finding LCM.

Step 5: Demonstration of Prime Factorization Method

Time: 7 minutes
Teaching Skill: Demonstration/Illustration
Teacher’s Activity: The teacher demonstrates finding the LCM of two numbers (e.g., 10 and 15) using the prime factorization method, showing how to find prime factors for each number and then combining them to get the LCM.
Pupils’ Activity: Pupils observe carefully and ask questions about the steps.
Learning Point: Pupils learn to apply the prime factorization method to find LCM.

Step 6: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

What does LCM stand for?
Define the term “Least Common Multiple.”
List the steps involved in finding the LCM using the multiples method.
Find the LCM of 9 and 12 using any method.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 7: Conclusion

Time: 3 minutes
Teaching Skill: Summarization
Teacher’s Activity: The teacher summarizes the lesson by reiterating the definition of LCM and the two methods discussed (multiples and prime factorization). The teacher assigns homework: Find the LCM of (a) 6 and 8, (b) 10 and 25.
Pupils’ Activity: Pupils listen to the summary and copy down the homework assignment.
Learning Point: Pupils consolidate their understanding of the lesson.

Home Task: Solve three new exercises on L. C. M. Show each step and check each answer.

Lesson Keywords

LCM – Stands for Least Common Multiple, the smallest number that is a multiple of two or more numbers.
Multiple – The result of multiplying a number by an integer (e.g., multiples of 3 are 3, 6, 9, 12…).
Common Multiple – A number that is a multiple of two or more different numbers.
Factor – A number that divides another number exactly without leaving a remainder.
Prime Factorization – The process of breaking down a number into its prime factors.

Differentiation

For pupils who are struggling, the teacher will provide additional simpler examples and work through them step-by-step. They will be encouraged to focus on the multiples method first. For advanced pupils, the teacher will provide more challenging problems involving three numbers or slightly larger numbers, and encourage them to explain their reasoning for both methods.

Note for teachers using this lesson plan

Ensure pupils have a solid understanding of basic multiplication tables and the concept of multiples before introducing LCM. Use visual aids like number charts to help pupils identify multiples. Encourage active participation and peer learning. Provide ample practice problems for both methods. Emphasize that the LCM is always greater than or equal to the numbers given.