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Subject: Mathematics
Semester: 2
Period: 4
Week: 20
School Name:
Teacher’s Name:
Subject: Mathematics
Grade Level: Grade 1
Date: Week 20
Lesson Duration: 45 minutes
Week & Period: Week 20, Period 4
Topic: Addition
Sub-topic: Adding Two-Digit Numbers without Regrouping
Learning Objectives
By the end of the lesson, students should be able to:
Add 2-digit numbers without regrouping
Use horizontal and vertical addition methods
Solve simple addition word problems
Previous Knowledge
Students already know place value of tens and ones and can add multiples of 10
Instructional Materials
Mathematics textbook, base 10 blocks, place value charts
Lesson Development – ABC Model
A – Anticipation (Warm-up / Starter)
Time: 5–10 minutes
Teacher writes 20 + 30 and asks students to solve mentally. Teacher then asks: “What is 24 + 35?” to introduce the new lesson.
B – Building Knowledge (Main Lesson Body)
Time: 25–30 minutes
Adding two-digit numbers without regrouping means that the sum of ones is less than 10. Example: 24 + 35
Step 1: Write the numbers in vertical form:
24
+35
Step 2: Add ones: 4 + 5 = 9
Step 3: Add tens: 2 tens + 3 tens = 5 tens
Answer = 59
Word problem example: Bola has 23 pencils. Musa gives her 15 more. How many pencils does Bola have in total? 23 + 15 = 38.
Learners’ Activities (Expanded)
Students solve addition examples using base 10 blocks.
Students write solutions in both horizontal and vertical formats.
Students solve simple word problems in pairs.
Assessment Checks
Teacher asks: “What is 42 + 13?” “What is 25 + 21?”
Students explain steps aloud.
Notes (Expanded & Detailed)
No regrouping occurs when the ones add up to less than 10. Encourage children to always start from ones before moving to tens.
C – Consolidation (Conclusion & Assessment)
Time: 5–10 minutes
Summary: Students recall that when adding two-digit numbers without regrouping, we add ones first, then tens.
Evaluation Method (Expanded)
Exit slip/quiz: Solve 34 + 25 and 41 + 12. Teacher checks and gives oral corrections.
Assignment (Expanded)
Solve 10 exercises from the textbook (5 horizontal, 5 vertical).
Follow-up Activity
Students create 3 of their own addition word problems and solve them.
Differentiation / Inclusive Strategies
Weaker learners use place value charts. Stronger learners attempt sums with larger numbers.
Teacher’s Reflection (After Class)
What worked well? ___________________________________________
What needs improvement? ____________________________________
Students’ engagement level: ☑ High ☑ Medium ☑ Low