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Subject: Mathematics
Semester: 2
Period: 4
Week: 19
School Name:
Teacher’s Name:
Subject: Mathematics
Grade Level: Grade 4
Date: Week 19
Lesson Duration: 45 minutes
Week & Period: Week 19, Period 4
Topic: Multiplying multiples of 10’s, 100’s, and 1000’s
Sub-topic: Using place value to multiply large numbers
Learning Objectives
By the end of the lesson, students should be able to:
- Understand multiplication of numbers involving multiples of 10, 100, and 1000.
- Use place value to simplify multiplication problems.
- Solve real-life problems involving multiples of 10, 100, and 1000.
Previous Knowledge
Students already know multiplication of 1-digit and 2-digit numbers.
Instructional Materials
Mathematics textbook for Grade 4, number charts, place value charts, counters.
Lesson Development – ABC Model
A – Anticipation (Warm-up / Starter)
Time: 5–10 minutes
Teacher asks: “What is 3 × 4?” Then builds to “What is 30 × 40?” to trigger prior knowledge of zeros in multiplication. Students brainstorm with quick mental sums.
B – Building Knowledge (Main Lesson Body)
Time: 25–30 minutes
Teacher explains that when multiplying multiples of 10, 100, or 1000, the process can be simplified by temporarily ignoring the zeros, multiplying the non-zero digits, then adding the zeros back to the product at the end. This method uses place value understanding and reduces complexity in calculations.
Example 1:
30 × 40
Step 1: Ignore zeros → 3 × 4 = 12
Step 2: Count zeros ignored (1 zero in 30 and 1 zero in 40 = 2 zeros total)
Step 3: Add back two zeros → 12 becomes 1200
Example 2:
120 × 50
Step 1: Ignore zeros → 12 × 5 = 60
Step 2: Count zeros ignored (1 zero in 120, 1 zero in 50 = 2 zeros)
Step 3: Add back two zeros → 60 becomes 6000
Example 3:
1200 × 30
Step 1: Ignore zeros → 12 × 3 = 36
Step 2: Count zeros ignored (2 zeros in 1200, 1 zero in 30 = 3 zeros)
Step 3: Add back three zeros → 36 becomes 36000
Teacher models this visually with place value charts:
- Place digits 3 and 4 on the chart for 30 and 40 respectively, then show how multiplying 3 by 4 gives 12.
- Then demonstrate shifting digits left by the total number of zeros (2 zeros means moving digits two places to the left, resulting in 1200).
- Emphasize that zeros represent place value shifts, making the multiplication easier.
Practical Example:
In a supermarket, a bag of rice costs 30 Naira. How much will 40 bags cost?
Solution:
Ignore zeros → 3 × 4 = 12
Add back the two zeros → 1200 Naira
So, 40 bags cost 1200 Naira.
Additional Examples:
Example 4: 250 × 200
Ignore zeros → 25 × 2 = 50
Zeros ignored: 1 in 250 and 2 in 200 = 3 zeros
Add back three zeros → 50,000
Example 5: 600 × 700
Ignore zeros → 6 × 7 = 42
Zeros ignored: 2 in 600 and 2 in 700 = 4 zeros
Add back four zeros → 420,000
Example 6: 5000 × 90
Ignore zeros → 5 × 9 = 45
Zeros ignored: 3 in 5000 and 1 in 90 = 4 zeros
Add back four zeros → 450,000
Learners’ Activities (Expanded):
- Students work in pairs to multiply the following, showing all steps:
- 20 × 50
- 400 × 30
- 250 × 200
- 600 × 70
- 1,200 × 300
- Students model multiplication using counters or base-ten blocks grouped in tens, hundreds, and thousands to visualize how zeros shift the digits.
- Use place value charts:
- Write numbers with zeros on charts.
- Multiply the base numbers (ignoring zeros).
- Shift the product left by the number of zeros to find the final answer.
- Word problem activity:
- A farmer packs 40 crates with 120 apples each. How many apples are packed in total? (40 × 120)
- A factory produces 300 items every day for 50 days. How many items are produced? (300 × 50)
Assessment Checks:
- What is 60 × 200?
(Answer: Ignore zeros → 6 × 2 = 12; add two zeros → 12,000) - How can you simplify 120 × 400 before multiplying?
(Expected: Ignore zeros → 12 × 4 = 48; add back three zeros → 48,000) - Calculate 500 × 600 using the method shown.
- If a notebook costs 70 Naira, how much do 500 notebooks cost?
- Multiply 1,500 × 20 using place value understanding.
Notes (Expanded & Detailed):
Multiplying multiples of 10, 100, and 1000 becomes easier when you:
• Ignore the zeros initially to focus on the non-zero digits.
• Multiply these smaller numbers as usual.
• Add back the total number of zeros you ignored to the end of the product.
This method works because zeros represent the place value shifts (multiplying by powers of 10). This process helps avoid errors and simplifies calculations, especially when dealing with large numbers.
Teachers should emphasize that this method saves time and reinforces understanding of place value, essential for more advanced math operations.
Practical application of this concept in real life includes calculating prices for bulk items, quantities in factories, and large-scale data in science or economics.
C – Consolidation (Conclusion & Assessment)
Time: 5–10 minutes
Summary: Multiplication involving multiples of 10, 100, and 1000 can be solved quickly using place value understanding.
Evaluation Method (Expanded):
Exit slip/quiz: Solve 70 × 200 and 1200 × 50.
Teacher will collect slips and provide oral feedback.
Assignment (Expanded):
- Multiply 40 × 300.
- Multiply 250 × 200.
- A box contains 120 pencils. Find the total in 30 boxes.
Follow-up Activity:
Students practice with shopping and money-related problems.
Differentiation / Inclusive Strategies
Struggling learners get step-by-step guidance with smaller numbers. Advanced learners solve real-life word problems with larger values.
Teacher’s Reflection (After Class)
What worked well? ___________________________________________
What needs improvement? ____________________________________
Students’ engagement level: ☑ High ☑ Medium ☑ Low