B6 Mathematics · Term 1, Week 7

Counting, Representation, Cardinality & Ordinality

Lesson notes

Learning Objectives

Indicator: B6.1.1.3.1 - Determine the HCF and the LCM of two or three numbers using prime factors

By the end of the lesson, learners can:

Find the prime factors of any whole number between 1 and 100 using a factor tree method.
Determine the Highest Common Factor (HCF) of two or three numbers by identifying common prime factors.
Determine the Lowest Common Multiple (LCM) of two or three numbers by identifying the largest set of each prime factor.
Use a factor table to find the HCF and LCM of three numbers.
Apply HCF and LCM to solve simple word problems in everyday situations.

Curriculum details

Strand: Number (Strand 1)
Sub-strand: Counting, Representation, Cardinality & Ordinality (1.1)
Content standard: B6.1.1.3 - Demonstrate understanding of factors, multiples and prime numbers from 1 to 100
Indicator: B6.1.1.3.1 - Determine the HCF and the LCM of two or three numbers using prime factors
Suggested placement: Term 1, Week 7 (Week 7 of the year)
Our suggestion, laid out in curriculum order across three terms of twelve weeks. NaCCA does not fix the week, so follow your school's scheme of learning.
Curriculum reference: Mathematics Curriculum for Primary Schools (Basic 4-6), 2019, p. 121
Transcribed from the official NaCCA publication. Check this page against the source.

Exemplars (from the NaCCA curriculum)

E.g. 1 Have learners revise the use of the factor tree method to determine prime factors of any given whole number. For example the prime factors of 24. For instance, from the figure: 24 = 2×2×2×3 so 2 and 3 are the prime factors of 24. Ask learners to list the factors of two or more given whole numbers using the factor tree; for 36 and 48 we have 36= 2×3×2×3 =2×2×3×3 and 48= 2×3×2×2×2 = 2×2×2×2×3.

Wide colour mathematical teaching visual is organised as a table with horizontal divisions, vertical divisions,... — A wide colour mathematical teaching visual is organised as a table with horizontal divisions, vertical divisions, coloured regions. Visible labels, values, and notation include: E.g. 1; Have learners revise the use of the factor tree method to determine prime factors of any given; whole number. For example the prime factors of; 24; 24. For instance, from the figure: 24 = 2×2×2×3; so 2 and 3 are the prime factors of.

E.g. 2 Learners use the prime factorization by inspection to determine the HCF by underlining the common factors in each product 36=2×2×3×3 48= 2×2×2×2×3 → which is 2×2×3=12;

Wide black-and-white mathematical teaching visual is organised as a table with horizontal divisions, vertical... — A wide black-and-white mathematical teaching visual is organised as a table with horizontal divisions, vertical divisions. Visible labels, values, and notation include: inspection to determine the HCF by; underlining the common factors in each; product; 36=2×2×3×3; 48=2×2×2×2×3; 36; 6; 8; 2; 32; 3; → which is 2×2×3=12; E.g. 3 Learners use the prime factorization by inspection to determine the LCM and underlining the.

E.g. 3 Learners use the prime factorization by inspection to determine the LCM and underlining the largest number of factors in each product 36=2×2×3×3 48= 2×2×2×2×3 → which is 2×2×2×2×3×3=144

E.g. 4 Learners place factors in a Venn diagrams to find the HCF and LCM of 36 and 48. i.e. the HCF is product of factors in both circles →2×2×3=12; and the LCM is product of factors in the diagram →3×2×2×3×2×2 =144
E.g. 5 Learners use the prime factorisation to determine the LCM and HCF of three numbers using table and dividing through by prime factors. Example 1, find the LCM and HCF these sets of numbers: 18, 24 and 30. Using prime factorization table - (see method in figure), i.e. HCF = 2×3 = 4, and LCM = 2×2×2×3×3×5 = 360.

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