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Subject: Mathematics
Semester: 2
Period: 4
Week: 19
School Name:
Teacher’s Name:
Subject: Mathematics
Grade Level: Grade 1
Date: Week 19
Lesson Duration: 45 minutes
Week & Period: Week 19, Period 4
Topic: Addition and Subtraction
Sub-topic: Adding and Subtracting Multiples of 10
Learning Objectives
By the end of the lesson, students should be able to:
Add multiples of 10 up to 100
Subtract multiples of 10 up to 100
Recognize and use patterns when adding or subtracting multiples of 10
Previous Knowledge
Students already know how to count in tens up to 100 and identify multiples of 10
Instructional Materials
Mathematics textbook for Grade 1, number line, base 10 blocks, flashcards with multiples of 10
Lesson Development – ABC Model
A – Anticipation (Warm-up / Starter)
Time: 5–10 minutes
Teacher asks students to count aloud in tens up to 100. Students use their fingers to show multiples of 10. Teacher then asks: “What comes after 20?” “What comes before 50?” to refresh recall.
B – Building Knowledge (Main Lesson Body)
Time: 25–30 minutes
Addition of multiples of 10 means combining two or more tens together. Example: 20 + 30 = 50. Using base 10 blocks, 2 rods of 10 and 3 rods of 10 make 5 rods of 10 which is 50.
Subtraction of multiples of 10 means taking away tens. Example: 80 – 40 = 40. On the number line, move backwards in steps of 10.
Patterns: When adding multiples of 10, the ones digit always stays 0. Example: 40 + 30 = 70. When subtracting multiples of 10, the ones digit also remains 0. Example: 90 – 20 = 70.
Learners’ Activities (Expanded)
Students use counters and number lines to solve 30 + 40 and 70 – 30.
Students practice addition and subtraction in pairs using flashcards.
Students explain the observed patterns in their own words.
Assessment Checks
Teacher asks oral questions such as: “What is 50 + 20?” “What is 60 – 40?”
Teacher gives quick written exercises to check understanding.
Notes (Expanded & Detailed)
Adding and subtracting multiples of 10 makes use of counting in tens. Students must clearly see that the ones digit remains unchanged. Use practical models like rods and number lines to help weaker learners.
C – Consolidation (Conclusion & Assessment)
Time: 5–10 minutes
Summary: Students recall that adding multiples of 10 means moving forward in tens and subtracting multiples of 10 means moving backwards in tens. The ones digit remains 0.
Evaluation Method (Expanded)
Exit slip/quiz: Teacher writes 3 questions on the board (e.g. 30 + 40, 90 – 20, 50 + 10) and students solve them on slips of paper. Teacher will collect slips and provide oral feedback.
Assignment (Expanded)
Students solve 5 addition and 5 subtraction problems involving multiples of 10 from their textbook.
Follow-up Activity
Students practice counting forward and backward in tens at home with a family member.
Differentiation / Inclusive Strategies
Weaker learners use base 10 blocks and number lines. Stronger learners solve mentally and explain their reasoning.
Teacher’s Reflection (After Class)
What worked well? ___________________________________________
What needs improvement? ____________________________________
Students’ engagement level: ☑ High ☑ Medium ☑ Low