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Subject: Mathematics
Semester: 1
Period: 1
Week: 3
School Name:
Teacher’s Name:
Subject: Mathematics
Grade Level: Grade 1
Date: Week 3
Lesson Duration: 45 minutes
Week & Period: Week 3, Period 1
Topic: Union of Sets
Sub-topic: Introduction to Union and Notation
Learning Objectives
By the end of the lesson, students should be able to:
Explain the meaning of union
Identify and combine two sets
Use the union symbol ( ∪ )
Previous Knowledge
Students already know:
What a set is
How to count the number of elements in a set
Instructional Materials
Mathematics textbook for Grade 1
Lesson Development – ABC Model
A – Anticipation (Warm-up / Starter)
Time: 5–10 minutes
Teacher brings two baskets: one with apples, one with bananas. Teacher asks, “What will happen if we put them together?”
B – Building Knowledge (Main Lesson Body)
Time: 25–30 minutes
Definition: The union of two sets means putting all elements together in one set.
We use the union symbol ∪
Example:
Set A = {boys}
Set B = {girls}
A ∪ B = {class members}
Set C = {mango, banana}
Set D = {carrot, tomato}
C ∪ D = {mango, banana, carrot, tomato} → all food items
Notation:
If A = {1, 2} and B = {3, 4}, then A ∪ B = {1, 2, 3, 4}
Learners’ Activities (Expanded):
Students form two sets (boys and girls), then come together as one set (union)
Students group objects (e.g., crayons and pencils), then find the union
Group role play: “Set A meets Set B” and they combine
Assessment Checks:
Teacher gives two sets and asks students to find the union
Teacher checks use of symbol ∪ and correct listing of all members
Notes (Expanded & Detailed):
Union brings everything from both sets
No repetition in union
The union symbol is ∪
C – Consolidation (Conclusion & Assessment)
Time: 5–10 minutes
Summary: Union of sets means joining everything from both sets. We use ∪ to show it.
Evaluation Method (Expanded):
Exit slip/quiz: Find A ∪ B if A = {2, 4} and B = {3, 5}
Teacher will collect slips and provide oral feedback.
Assignment (Expanded):
Draw two sets of objects from your home and write their union.
Follow-up Activity:
Next lesson will introduce subsets and subtraction
Differentiation / Inclusive Strategies
Allow use of drawings and real items for learners who need visual/tactile aid. Let students explain in local language if needed.
Teacher’s Reflection (After Class)
What worked well? ___________________________________________
What needs improvement? ____________________________________
Students’ engagement level: ☑ High ☑ Medium ☑ Low