Understanding Multiplication of Whole Numbers Mathematics Primary 4 First Term Lesson Notes Week 8

Mathematics Primary 4 First Term Lesson Notes Week 8

Subject: Mathematics
Class: Primary 4
Term: First Term
Week: 8
Age: 9 years
Topic: Multiplication of Whole Numbers
Sub-topic: Multiplying Whole Numbers by 2-Digit Numbers
Duration: 1 hour

Behavioural Objectives:

• Revise basic multiplication facts.
• Multiply whole numbers by 2-digit numbers using grid and vertical methods.
• Apply multiplication to solve real-life and quantitative reasoning problems.

Keywords: Multiplication, Grid method, Vertical method, Whole numbers, Quantitative reasoning.

Set Induction: Start by discussing situations where multiplication is needed, such as calculating total cost of items when buying in bulk.

Entry Behaviour: Pupils should be familiar with basic multiplication facts and single-digit multiplication.

Learning Resources and Materials:

• Multiplication charts
• Worksheets for grid and vertical methods
• Real-life problem cards
• Whiteboard and markers

Building Background / Connection to Prior Knowledge: Review single-digit multiplication facts and their application in real-life scenarios to prepare for multiplication with larger numbers.

Embedded Core Skills:

• Numerical calculation
• Problem-solving
• Application of multiplication in various contexts

Learning Materials:

• Grid and vertical method practice worksheets
• Examples of real-life multiplication problems
• Multiplication charts

Reference Books:

• Lagos State Scheme of Work

Instructional Materials:

• Multiplication worksheets
• Real-life problem scenarios
• Grid and vertical method guides

Content:

1. Basic Multiplication Facts Review:
   • Explanation: Revisit multiplication tables and basic facts (e.g., 2×3=6, 5×4=20).
   • Example: Multiplying single-digit numbers to refresh basic skills.
2. Multiplying Whole Numbers Using the Vertical Method:
   • Explanation: Multiply whole numbers by 2-digit numbers.
   • Example: 62 × 24. Break into steps:
     • 62 × 4 = 248
     • 62 × 20 = 1240
     • Add results: 248 + 1240 = 1488
3. Multiplying Whole Numbers Using the Grid Method:
   • Explanation: Use the grid method to multiply. Break numbers into tens and units, multiply, then add results.
   • Example: 62 × 24.
     • Break 62 into 60 + 2 and 24 into 20 + 4.
     • Multiply each combination:
       • (60 × 20) = 1200
       • (60 × 4) = 240
       • (2 × 20) = 40
       • (2 × 4) = 8
     • Add results: 1200 + 240 + 40 + 8 = 1488
4. Real-Life Problems and Quantitative Reasoning:
   • Explanation: Apply multiplication to real-life scenarios such as calculating costs, area, or quantities.
   • Example: If one book costs $12 and you buy 15 books, the total cost is 12 × 15 = $180.

Evaluation:

1. 62 × 24 = _____. (a) 1488 (b) 1200 (c) 1400 (d) 1248
2. Using the vertical method, 45 × 23 = _____. (a) 1035 (b) 1025 (c) 1045 (d) 1055
3. If you multiply 34 by 56 using the grid method, the result is _____. (a) 1904 (b) 1894 (c) 1914 (d) 1924
4. 87 × 29 = _____. (a) 2523 (b) 2513 (c) 2533 (d) 2543
5. Using the grid method, 53 × 12 = _____. (a) 636 (b) 624 (c) 642 (d) 630
6. Multiply 78 by 45. The result is _____. (a) 3510 (b) 3600 (c) 3540 (d) 3550
7. 91 × 32 = _____. (a) 2912 (b) 2902 (c) 2920 (d) 2932
8. 56 × 43 = _____. (a) 2408 (b) 2418 (c) 2448 (d) 2458
9. Using the vertical method, 82 × 37 = _____. (a) 3034 (b) 3044 (c) 3054 (d) 3064
10. Multiply 68 by 24. The result is _____. (a) 1632 (b) 1624 (c) 1642 (d) 1612
11. 39 × 76 = _____. (a) 2964 (b) 2974 (c) 2984 (d) 2994
12. Using the grid method, 47 × 58 = _____. (a) 2726 (b) 2736 (c) 2746 (d) 2756
13. 63 × 29 = _____. (a) 1827 (b) 1837 (c) 1847 (d) 1857
14. Multiply 74 by 32. The result is _____. (a) 2368 (b) 2378 (c) 2388 (d) 2398
15. 89 × 54 = _____. (a) 4806 (b) 4816 (c) 4826 (d) 4836

Class Activity Discussion:

1. Q: How do you use the vertical method for multiplication?
   A: Write the numbers in columns, multiply each digit, and add the results.
2. Q: What is the grid method for multiplication?
   A: Break numbers into parts, multiply each part, then add the results.
3. Q: Why is it useful to know both multiplication methods?
   A: Different methods can help check results and understand multiplication better.
4. Q: How can you apply multiplication in real life?
   A: For calculating costs, measuring areas, or determining quantities in bulk.
5. Q: What are some common mistakes in multiplication?
   A: Misaligning numbers, forgetting to carry over, or misplacing decimal points.
6. Q: How do you check your multiplication answers?
   A: Use the reverse operation (division) to verify your result.
7. Q: Can you use multiplication for financial calculations?
   A: Yes, for tasks like calculating total expenses, interest, or currency conversion.
8. Q: What strategies can help with large multiplication problems?
   A: Break numbers into smaller parts and multiply each part separately.
9. Q: How does multiplication help in professions like banking or finance?
   A: It helps in calculating amounts, interest rates, and financial projections.
10. Q: How can practicing multiplication improve your math skills?
    A: It enhances problem-solving abilities and understanding of numerical relationships.

Presentation:

1. Step 1: Review basic multiplication facts and single-digit multiplication.
2. Step 2: Introduce and demonstrate the grid and vertical methods for multiplying whole numbers.
3. Step 3: Practice solving real-life problems and quantitative reasoning exercises using multiplication.

Teacher’s Activities:

• Explain and demonstrate multiplication methods.
• Provide practice problems and facilitate discussions.
• Assist pupils with solving real-life multiplication problems.

Topic: Multiplication

1. Revising Basic Multiplication Facts

What is Multiplication?

• Multiplication is a way to add the same number multiple times. For example, 4 × 3 means adding 4 three times: 4 + 4 + 4 = 12.

Basic Multiplication Facts:

• Practice multiplying small numbers to become quick and accurate.
  • Example:
    • 3 × 5 = 15
    • 7 × 8 = 56

2. Multiplying Whole Numbers by 2-Digit Numbers

Method 1: Vertical Method

Example: Multiply 62 by 24

Steps:

1. Write the numbers in a column:
   • 62
   • × 24

   ---

2. Multiply 62 by 4 (units place):
   • 62 × 4 = 248
   • Write 248 under the line.
3. Multiply 62 by 2 (tens place):
   • 62 × 2 = 124
   • Shift this result one place to the left (because it’s in the tens place).
   • Write 1240 under the first result.
4. Add the two results:
   • 248
   • +1240

   ---

   • 1488

Practice Problem:

• Multiply 45 by 32.

Method 2: Grid Method

Example: Multiply 62 by 24

Steps:

1. Break down the numbers:
   • 62 = 60 + 2
   • 24 = 20 + 4
2. Create a grid:
   • | | 60 | 2 |
   • |——-|—-|—-|
   • | 20 | 1200 | 40 |
   • | 4 | 240 | 8 |
3. Fill in the grid by multiplying:
   • 60 × 20 = 1200
   • 60 × 4 = 240
   • 2 × 20 = 40
   • 2 × 4 = 8
4. Add the results from the grid:
   • 1200
   • • 240
   • • 40
   • • 8

   ---

   • 1488

Practice Problem:

• Multiply 54 by 23 using the grid method.

3. Importance of Multiplication

• Banking and Finance: Multiplication helps in calculating interest rates, loans, and budgets.
• Foreign Exchange: Used for converting currencies.
• Buying and Selling: Helps in calculating total costs, discounts, and prices.

Example:

• If a toy costs 15 naira and you buy 8 toys, you use multiplication to find the total cost: 15 × 8 = 120 naira.

4. Solving Real-Life Problems

Example 1:

• Problem: You have 6 packs of pencils. Each pack contains 12 pencils. How many pencils do you have in total?
  • Solution:
    • 6 × 12 = 72 pencils

Example 2:

• Problem: A box contains 24 chocolates. If you buy 5 boxes, how many chocolates do you have?
  • Solution:
    • 24 × 5 = 120 chocolates

Practice Problem:

• If each student in a class of 30 has 5 pencils, how many pencils are there in total?

Practice Questions:

1. Multiply: 23 × 15
   • a) 345
   • b) 350
   • c) 335
2. Using the grid method, find the product of 45 × 32.
   • a) 1440
   • b) 1445
   • c) 1448
3. You buy 8 books, each costing 50 naira. How much do you spend in total?
   • a) 400 naira
   • b) 450 naira
   • c) 500 naira
4. If you have 7 packs of markers and each pack has 6 markers, how many markers do you have?
   • a) 42
   • b) 40
   • c) 48

Learners’ Activities:

• Solve multiplication problems using grid and vertical methods.
• Apply multiplication to real-life scenarios.
• Participate in group discussions and problem-solving activities.

Assessment:

• Check pupils’ ability to use multiplication methods accurately.
• Evaluate understanding through practice problems and real-life applications.

Evaluation Questions:

1. What is 62 × 24? (a) 1488 (b) 1200 (c) 1400 (d) 1248
2. How do you solve 45 × 23 using the vertical method? (a) 1035 (b) 1025 (c) 1045 (d) 1055
3. What is the result of 34 × 56? (a) 1904 (b) 1894 (c) 1914 (d) 1924
4. Multiply 87 by 29. What do you get? (a) 2523 (b) 2513 (c) 2533 (d) 2543
5. How do you solve 53 × 12 using the grid method? (a) 636 (b) 624 (c) 642 (d) 630
6. What is 78 × 45? (a) 3510 (b) 3600 (c) 3540 (d) 3550
7. What is 91 × 32? (a) 2912 (b) 2902 (c) 2920 (d) 2932
8. Multiply 56 by 43. The result is? (a) 2408 (b) 2418 (c) 2448 (d) 2458
9. How do you calculate 82 × 37 using the vertical method? (a) 3034 (b) 3044 (c) 3054 (d) 3064
10. What is the result of 68 × 24? (a) 1632 (b) 1624 (c) 1642 (d) 1612
11. What do you get when multiplying 39 × 76? (a) 2964 (b) 2974 (c) 2984 (d) 2994
12. How do you solve 47 × 58 using the grid method? (a) 2726 (b) 2736 (c) 2746 (d) 2756
13. What is the product of 63 and 29? (a) 1827 (b) 1837 (c) 1847 (d) 1857
14. What is 74 × 32? (a) 2368 (b) 2378 (c) 2388 (d) 2398
15. Multiply 89 by 54. What do you get? (a) 4806 (b) 4816 (c) 4826 (d) 4836

Conclusion: The teacher will review pupils’ work, provide feedback, and ensure they understand both multiplication methods and their applications.