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Subject: Mathematics
Semester: 1
Period: 2
Week: 10
School Name:
Teacher’s Name:
Subject: Mathematics
Grade Level: Grade 6
Date: Week 10
Lesson Duration: 45 minutes
Week & Period: Week 10, Period 2
Topic: Multiplication in Base Ten
Sub-topic: Long Multiplication
Learning Objectives
By the end of the lesson, students should be able to:
Multiply numbers in base ten (long multiplication)
Apply multiplication to word problems
Use multiplication in practical scenarios
Previous Knowledge
Students already know multiplication tables and basic multiplication facts.
Instructional Materials
Mathematics textbook for Grade 6, chart paper, worksheets.
Lesson Development – ABC Model
A – Anticipation (Warm-up / Starter)
Time: 5–10 minutes
Teacher asks: “Multiply 23 × 4 mentally. How about 23 × 12?” Introduce long multiplication.
B – Building Knowledge (Main Lesson Body)
Time: 25–30 minutes
Definition
Long multiplication is a method used to multiply numbers with two or more digits. It is useful when mental multiplication or simple short multiplication is not sufficient. It involves breaking the process into smaller steps (partial products), which are then added together.
Step-by-Step Procedure
To multiply two numbers (e.g., 23 × 12):
- Write the numbers vertically, with the larger number on top:
- 23
× 12
- Multiply the bottom number’s ones digit (2) by each digit of the top number:
- 2 × 3 = 6
- 2 × 2 = 4
→ First row: 46
- Multiply the tens digit (1 in 12 = 10) by the top number:
- 1 × 3 = 3
- 1 × 2 = 2
→ Second row: 230 (shift one place to the left because it's a tens place)
- Add the two partial products:
46
+230
= 276
More Examples
Example 1:
34 × 15
Step 1:
34
× 15
Step 2: Multiply by 5 (ones digit):
- 5 × 4 = 20 → write 0, carry 2
- 5 × 3 = 15 + 2 = 17 → write 17
→ First row = 170
Step 3: Multiply by 1 (tens digit), shift one place:
- 1 × 4 = 4
- 1 × 3 = 3
→ Second row = 340
Step 4: Add:
170
+340
= 510
Answer: 34 × 15 = 510
Example 2 (3-digit × 2-digit):
125 × 23
Step 1:
125
× 23
Step 2: Multiply by 3 (ones digit):
- 3 × 5 = 15 → write 5, carry 1
- 3 × 2 = 6 + 1 = 7
- 3 × 1 = 3
→ First row = 375
Step 3: Multiply by 2 (tens digit = 20), shift one place:
- 2 × 5 = 10 → write 0, carry 1
- 2 × 2 = 4 + 1 = 5
- 2 × 1 = 2
→ Second row = 2500
Step 4: Add:
- 375
+2500
= 2875
Answer: 125 × 23 = 2875
Word Problems (Real-Life Application)
Example 1:
If 12 books cost 25 Liberian Dollars (LD) each, what is the total cost?
Solution:
12 × 25 = 300 LD
Example 2:
A farmer sells 18 baskets of oranges, each for 45 LD. How much does he earn in total?
18 × 45 = 810 LD
Example 3:
Each student in a class receives 17 notebooks. If there are 36 students, how many notebooks were distributed in total?
36 × 17 = 612 notebooks
Learners’ Activities (Expanded)
- Board Practice:
Students solve teacher-given examples on the board, e.g.,- 45 × 13
- 127 × 14
- 62 × 25
- Real-Life Word Problems:
Students are given problems related to shopping, farming, or school items and solve them using long multiplication. - Group Work (Pair & Share):
Learners work in pairs to create and solve two multiplication word problems and share answers with the class. - Self-Check & Peer Review:
Learners swap notebooks and check each other’s work for calculation errors and explain corrections if needed.
Assessment Checks
Oral Questions:
- "What is the first step in long multiplication?"
- "What do you do after multiplying by the tens digit?"
- "Multiply 46 × 12 quickly."
Quick Written Problems:
- Multiply:
- 54 × 21
- 135 × 12
- Solve:
- A pack of biscuits costs 36 LD. How much will 15 packs cost?
- Each desk costs 275 LD. What is the total cost for 8 desks?
- Fill in the blanks:
- In 23 × 14, the partial products are _____ and _____
- Final product is ______
Notes (Expanded & Detailed)
- Why Long Multiplication?
It is a reliable method for multiplying large numbers that cannot be done mentally. It helps students break down complex problems into manageable steps. - Common Mistakes to Watch For:
- Forgetting to shift the second row when multiplying by the tens digit
- Not carrying correctly in two-digit products
- Adding partial products incorrectly
- Tips for Learners:
- Always write numbers neatly in columns
- Double-check the alignment of digits when adding
- Practice daily to improve speed and accuracy
Assignments
Section A: Solve Using Long Multiplication
- 47 × 16
- 85 × 19
- 123 × 34
- 62 × 45
Section B: Solve Word Problems
- A teacher buys 23 chairs at 125 LD each. How much does she spend?
- Each student needs 15 books. If there are 42 students, how many books are needed in total?
- A truck carries 235 sacks. Each sack weighs 17 kg. What is the total weight?
- A shopkeeper sells 38 bottles of oil daily. How many bottles are sold in 27 days?
C – Consolidation (Conclusion & Assessment)
Time: 5–10 minutes
Summary: Review steps of long multiplication, examples, and word problems.
Evaluation Method (Expanded)
Exit slip/quiz: Solve 26 × 14 and 37 × 23. Teacher provides oral feedback.
Assignment (Expanded):
Complete five long multiplication problems and one word problem using prices or quantities.
Follow-up Activity:
Practice multiplication with real-life objects (packs of items, money).
Differentiation / Inclusive Strategies
Stepwise guidance and visual aids for struggling learners; group activities for peer learning.
Teacher’s Reflection (After Class)
What worked well? ___________________________________________
What needs improvement? ____________________________________
Students’ engagement level: ☑ High ☐ Medium ☐ Low