L.C.M and H.C.F

Subject: 

MATHEMATICS

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Term:

FIRST TERM

Week:

WEEK 5

Class:

PRIMARY 6 / BASIC 6

Topic:

 LOWEST COMMON MULTIPLE (L.C.M)

HIGHEST COMMON FACTOR (H.C.F)

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Previous lesson: 

The pupils have previous knowledge of

 Learners are familiar with  multiples of numbers and factors of numbers 

that was taught as a topic in the previous lesson

Behavioural objectives:

At the end of the lesson, the learners will be able to

• say the meaning of H.C.F and L.C.M
• calculate the H.C.F and L.C.M of 2 or 3 digits using the multiple method
• calculate the H.C.F and L.C.M of 2 or 3 digits using the prime factors method
• solve real life problems on L.C.M and H.C.F

Instructional Materials:

• Wall charts
• Pictures
• Related Online Video
• Flash Cards
• Cardboard
• Understanding Mathematics Book Six.
• Multiplication table
• Charts on all factors of numbers and prime factors of number

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Methods of Teaching:

• Class Discussion
• Group Discussion
• Asking Questions
• Explanation
• Role Modelling
• Role Delegation

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Reference Materials:

• Scheme of Work
• Online Information
• Textbooks
• Workbooks
• 9 Year Basic Education Curriculum
• Workbooks

Content:

Topic : Lowest Common Multiple (LCM) 

Ref. Book: Understanding Mathematics Book Six, Ugo C. Ugo,

Behavioural Objectives: At the end of the lesson, pupils should be able to

      *Recite multiples of numbers

      * Point out multiples of numbers

      *Write out common multiples of numbers

      *Solve simple mathematics questions on lowest common multiple of any given set of numbers

The least common multiple (LCM) and highest common factor (HCF) are two mathematical terms that describe specific ways of finding the smallest number that can be divided into a set of numbers. LCM is used to find the lowest common factors between several different numbers, while HCF is used to find the highest common factors between several different numbers. Both are important mathematical concepts that can be applied in a variety of situations and problems.

Multiple numbers are also known as products of numbers. They are the answers that we get when we multiply two figures with each other. Therefore, we can say that the second multiple of 8 is 16 (8❌2=16)

Write out the first five multiples of seven = 7, 14, 21, 28, and 35

Write out the first six multiples of 2=2, 4, 6, 8, 10, and 12

We may calculate the LCM of numbers by writing out the common multiples of the given figures or by dividing the figures by prime numbers

Question 1. Calculate the LCM of 3 and 4

Solution: write out the multiples of the given figures to 12rh position

3= 3, 6, 9, 12,15, 18, 21, 24, 27, 30, 33, 36,

4= 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48

Common multiples of 3 and 4 are 12, 24, and 36

Lowest common multiple of 3 and 4 is equal to 12

Or

 we can equally solve the question by dividing the given figures repeatedly by prime numbers like this

 

Presentation: The topic is presented step by step

Step 1: The teacher revises the previous topics.

Step 2: The teacher introduces the new topic.

Step 3: the teacher allows the pupils to give their own contributions and he corrects then when the needs arise.

Evaluation: Calculate the LCM of the following figures

 

Mathematically speaking, LCM and HCF refer to two fairly well-defined processes for finding the smallest number that multiply or divide into a set of other numbers. The LCM refers to finding the smallest whole number that will multiply into each of a set of numbers. For example, if you want to find the lowest common multiple between 6 and 12, you would start by multiplying them together (6*12 = 72). The smallest whole number that can be multiplied into 72 is 24. This is your LCM for 6 and 12.

WHAT IS THE LCM OF 10 AND 20.

The smallest number which is exactly divisible by 10 and 20 is the LCM. Multiples of 10 = 10, 20, 30, 40, 50, 60, 70, ….. Multiples of 20 = 20, 40, 60, 80, 100, 120, …. Hence, the LCM of 10 and 20 is 20.

HCF is the term used to describe the highest common factor, which refers to finding the largest whole number that can divide into each of a set of numbers evenly. For example, if you want to find the HCF between 2 and 3, you can start by taking their product

HCF is a little different, and refers to finding the smallest whole number that will divide into each of a set of numbers without leaving any remainder. For example, if you wanted to find the HCF for 2, 3, and 5, you would start by dividing these numbers together (2/3/5 = 0 remainder). The smallest number that can be divided into 3 and 5 is 1, so 1 is your HCF for 2, 3, and 5.

What is the HCF of 10 and 20.

HCF of 10 and 20 is 10. Because 10 is the greatest COMMON divisor of both the numbers.

10 goes with 10 and 10 goes with 20 too..