Further Mathematics - Senior Secondary 1 - Set theory (I)

Set theory (I)

TERM: 1ST TERM

WEEK 1

Class: Senior Secondary School 1
Age: 15 years
Duration: 40 minutes per period
Subject: Further Mathematics
Topic: Set Theory (I)
Focus: Introduction to sets, set notation, and types of sets.

SPECIFIC OBJECTIVES:
By the end of the lesson, students should be able to:

  1. Define what a set is.
  2. Recognize and understand different methods of representing sets using notation.
  3. Identify and classify various types of sets.
  4. Understand the concept of the number of elements in a set.

INSTRUCTIONAL TECHNIQUES:
• Question and answer
• Guided demonstration
• Class discussion
• Practice exercises
• Visual aids (charts)

INSTRUCTIONAL MATERIALS:
• Whiteboard and markers
• Charts illustrating different sets and their notations
• Flashcards with sets and types of sets
• Worksheets for set exercises

PERIOD 1 & 2: Introduction to Set Theory

PRESENTATION:

Step

Teacher’s Activity

Student’s Activity

Step 1 - Introduction to Sets

Introduces the concept of a set, explaining that a set is a well-defined collection of distinct objects. Explains that elements of a set are written in curly brackets.

Students listen attentively and ask questions for clarification.

Step 2 - Set Notation Methods

Introduces different ways to represent a set: roster (listing method) and set-builder notation. Examples: Roster: {1, 2, 3}, Set-builder: {x

x is an even number less than 5}.

Step 3 - Types of Sets

Explains the types of sets:

a) Null set (empty set) – A set with no elements.

b) Singleton set – A set with only one element. c) Finite set – A set with a countable number of elements.

d) Infinite set – A set with an uncountable number of elements.

e) Universal set – A set containing all elements under consideration for a particular context.

f) Power set – The set of all subsets of a given set.

g) Number of elements in a set – Cardinality of the set.

Students observe and write down the definitions and examples for each type of set.

Step 4 - Analogies and Real-Life Connections

Uses analogies to relate sets to real-life examples: e.g., a set of all students in the class (finite set), the set of all natural numbers (infinite set).

Students share their own analogies and examples related to sets.

NOTE ON BOARD:

  • Definition of a Set: A set is a well-defined collection of distinct objects.
  • Set Notations:
    • Roster Method: {a, b, c}
    • Set-builder Notation: {x | x is a prime number less than 10}
  • Types of Sets:
    • Null Set: Ø or {}
    • Singleton Set: {1}
    • Finite Set: {1, 2, 3}
    • Infinite Set: {1, 2, 3, ...}
    • Universal Set: U = {all elements under consideration}
    • Power Set: P(A) = {Ø, {1}, {2}, {1, 2}}
  • Number of Elements: The number of elements in a set is called its cardinality, denoted |A|.

Students copy the notes from the board.

EVALUATION (5 exercises):

  1. Define a set and provide an example.
  2. What does the cardinality of a set represent?
  3. What is the difference between a finite and an infinite set?
  4. Give an example of a universal set in your context.
  5. Explain the power set of the set {a, b}.

CLASSWORK (5 questions):

  1. Write down the set of even numbers between 1 and 10 in roster form.
  2. Identify if the set {1, 2, 3} is finite or infinite.
  3. Write the set of all prime numbers less than 20 in set-builder notation.
  4. How many elements are in the set {apple, banana, mango}?
  5. List the power set of {1, 2}.

ASSIGNMENT (5 tasks):

  1. Research and define a null set with an example.
  2. Explain why {a} is a singleton set.
  3. Write the universal set for the days of the week.
  4. Find the power set of {a, b, c}.
  5. What is the cardinality of the set of all odd numbers between 1 and 100?

PERIOD 3 & 4: Advanced Set Operations and Notation

PRESENTATION:

Step

Teacher’s Activity

Student’s Activity

Step 1 - Recap of Set Types

Quickly reviews the different types of sets from the previous lesson, focusing on any questions or clarifications needed.

Students engage with the teacher for clarification.

Step 2 - Operations on Sets

Introduces set operations:

union (A ∪ B),

intersection (A ∩ B), and

difference (A - B).

Uses visual aids (Venn diagrams) to explain these operations.

Students follow the teacher's demonstration, take notes, and participate in class exercises.

Step 3 - Number of Elements in Power Set

Explains how to calculate the number of elements in a power set using the formula

P(A)

Step 4 - Guided Practice

Provides examples of set operations (union, intersection, difference) and asks students to solve in pairs.

Students practice solving set operation problems in pairs.

NOTE ON BOARD:

  • Union of Sets (A ∪ B): The set containing all elements from both sets A and B.
  • Intersection of Sets (A ∩ B): The set containing only the elements that are in both sets A and B.
  • Difference of Sets (A - B): The set containing elements that are in set A but not in set B.
  • Power Set Formula: If A has n elements, then the number of elements in the power set of A is 2ⁿ.

EVALUATION (5 exercises):

  1. What is the union of sets {1, 2, 3} and {3, 4, 5}?
  2. What is the intersection of sets {a, b, c} and {b, c, d}?
  3. Find the difference between the sets {1, 2, 3, 4} and {2, 3}.
  4. How many elements are in the power set of {a, b}?
  5. Write the union of {2, 4, 6} and {1, 3, 5}.

CLASSWORK (5 questions):

  1. Find the intersection of {1, 2, 3} and {3, 4, 5}.
  2. Find the difference between {a, b, c} and {b, c, d}.
  3. Find the union of {x, y} and {z}.
  4. How many elements are in the power set of {a, b, c, d}?
  5. List the elements of the power set of {1, 2}.

ASSIGNMENT (5 tasks):

  1. Find the union of {1, 2, 3} and {2, 3, 4}.
  2. Find the intersection of {a, b} and {b, c}.
  3. List the power set of {p, q}.
  4. If A = {1, 2, 3, 4}, find the number of elements in the power set of A.

Solve for A ∩ B when A = {1, 3, 5} and B = {3, 4, 5}.