P6 Mathematics - Term I

Topic 1: Sets

Lesson 1: Introduction to Sets and Types of Sets

Duration: 45 minutes

Learning Objectives

By the end of this lesson, you will be able to:

• Define what a set is and identify sets in real-life situations
• Distinguish between equal sets and equivalent sets
• Identify unequal sets
• Use correct set notation and language to describe sets

Review: What is a Set?

A set is a collection of distinct objects or items.

Examples you see in this classroom:

• Set of all desks
• Set of all windows
• Set of all boys
• Set of all girls

Set Notation

We use curly brackets { } to write sets.

Examples:

A = {all desks in the classroom}
B = {all windows in the classroom}

Remember: Each item in a set is called an element or member.

Today's Focus

We will learn about three types of sets:

1. Equal sets
2. Equivalent sets
3. Unequal sets

Equal Sets

Definition:
Sets that have exactly the same elements

Key points:

• Same items
• Same number of items
• We use the symbol = for equal sets

Example: Equal Sets

Both sets contain the exact same items.

Another Example: Equal Sets

Set C = {2, 4, 6}
Set D = {2, 4, 6}

C = D (equal sets)

Why are they equal?
They have exactly the same numbers.

Your Turn: Think About It

Are these sets equal?

Set E = {desk 1, desk 2, desk 3}
Set F = {desk 1, desk 2, desk 3}

Discuss with your neighbor: What makes sets equal?

Answer: Equal Sets

Yes! E = F

Reason:
Both sets have exactly the same elements (desk 1, desk 2, and desk 3)

Remember: Equal = same items, same number

Equivalent Sets

Definition:
Sets that have the same number of elements but different items

Key points:

• Different items
• Same count (same number of items)
• We use the symbol ~ for equivalent sets

Example: Equivalent Sets

Same number of items (3 each), but different items.

Another Example: Equivalent Sets

Set C = {a, b, c}
Set D = {x, y, z}

C ~ D (equivalent sets)

Why are they equivalent?

• 3 items in each set
• But different letters

Equal vs Equivalent

Key difference: Equal sets have the SAME items.
Equivalent sets have DIFFERENT items but SAME count.

Your Turn: Think About It

Are these sets equal or equivalent?

Set G = {pen 1, pen 2, pen 3, pen 4}
Set H = {book 1, book 2, book 3, book 4}

Work individually: Write your answer in your exercise book.

Answer: Equivalent Sets

G ~ H (equivalent sets, not equal)

Reason:

• Both have 4 items (same number)
• But different items (pens vs books)

Unequal Sets

Definition:
Sets that have different numbers of elements

Key points:

• Different number of items
• May also have different items
• We use the symbol ≠ for unequal sets

Example: Unequal Sets

Set E has 3 items, Set F has 5 items.

Another Example: Unequal Sets

Set C = {1, 2}
Set D = {1, 2, 3}

C ≠ D (unequal sets)

Different number of items: 2 vs 3

Practice Activity

Your task:
Identify each pair of sets as equal (=), equivalent (~), or unequal (≠)

Write your answers in your exercise book.

Work individually (3 minutes)

Practice Questions

1. A = {boy 1, boy 2, boy 3}
   B = {boy 1, boy 2, boy 3}

2. C = {desk 1, desk 2, desk 3, desk 4}
   D = {chair 1, chair 2, chair 3, chair 4}

3. E = {book 1, book 2}
   F = {pen 1, pen 2, pen 3}

Write: 1. ___ 2. ___ 3. ___

Answers to Practice Questions

1. A = B (equal sets)
   Reason: Exactly the same elements

2. C ~ D (equivalent sets)
   Reason: Same number (4), different items

3. E ≠ F (unequal sets)
   Reason: Different number of items (2 vs 3)

Summary: Three Types of Sets

Key Vocabulary

• Set - A collection of distinct objects
• Element/Member - An item that belongs to a set
• Equal sets - Sets with exactly the same elements
• Equivalent sets - Sets with same count, different items
• Unequal sets - Sets with different numbers of elements

Homework

Assignment:

1. Look around your home and find 3 examples of sets
2. Create and draw:
   • One pair of equal sets
   • One pair of equivalent sets
   • One pair of unequal sets
3. Write the correct symbol: =, ~, or ≠

Expected time: 15-20 minutes

Next Lesson Preview

Tomorrow we will learn about:

• Universal sets
• Complement sets
• Subsets

Bring your exercise book with today's homework!

Credits

Created: November 21, 2025
Based on: NCDC P6 Mathematics Curriculum - Topic 1: Sets

Source: National Curriculum Development Centre (NCDC), Uganda

Available from: https://ncdc.go.ug/