Lesson Notes By Weeks and Term v4 - JHS 2
Number and Numeration Systems
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Number and Numeration Systems
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Subject: Mathematics
Class: JHS 2
Term: 1st Term
Week: 5
Grade code: B8.1.1.2.2
Strand code: 3
Sub-strand code: 1
Content standard code: B8.1.1.2
Indicator code: B8.1.1.2.2
Theme: GEOMETRY AND MEASUREMENT
Subtheme: Number and Numeration Systems
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This lesson connects two important ideas we have learned: sets (grouping things) and factors/multiples (properties of numbers). We will learn how to use the language of sets to systematically find the Highest Common Factor (HCF) and the Lowest Common Multiple (LCM) of numbers. This skill is very useful in everyday life in Ghana, from sharing items fairly among friends without leftovers, to planning events, to understanding schedules like when the next two tro-tros will arrive at the station at the same time. Mastering this helps us solve real-world problems neatly and efficiently.
A. Recap: What are Sets and Factors? Set: A set is a collection of well-defined, distinct items or numbers. We write sets using curly braces `{}`. *Example:* The set of the first five even numbers is E = {2, 4, 6, 8, 10}. Factor: A factor of a number is any whole number that divides it exactly, leaving no remainder. *Example:* To find the factors of 12, we think of pairs of numbers that multiply to give 12: 1 × 12 = 12 2 × 6 = 12 3 × 4 = 12 So, the factors of 12 are 1, 2, 3, 4, 6, and 12. B. Finding the Highest Common Factor (HCF) using Sets The HCF of two or more numbers is the largest factor that they have in common. We can find this using the intersection of sets.
Steps: List all the factors for each number. Write these lists as sets. Let's call them `F_number`. Find the intersection (∩) of these sets. The intersection is the set of all elements that are common to all the sets. The HCF is the largest number (the highest value) in the intersection set.