PRIMARY 3: MATHEMATICS – SECOND TERM | WEEK 2

TOPIC: MULTIPLICATION OF THREE WHOLE NUMBERS

A: TEACHING AND LEARNING MATERIALS

1. Multiplication chart.
2. Number flashcards.
3. Counters.
4. Bundles of sticks.
5. Pupils’ writing books and pencils.

B: REFERENCE MATERIALS

1. Scheme of work.
2. Recommended Mathematics textbook for Primary 3.
3. Online educational resources.

C: PREVIOUS KNOWLEDGE

The pupils can multiply two whole numbers and recall simple multiplication tables.

D: PERFORMANCE OBJECTIVES

By the end of the lesson, pupils should be able to:

1. Multiply three one-digit numbers.
2. Multiply two numbers at a time.
3. Change the order of factors without changing the answer.
4. group factors in different ways.
5. Solve simple word problems involving three factors.

E: CONTENT

Multiplying Three Numbers

To multiply three numbers, we multiply two numbers first, then multiply the answer by the third number.
Example:

2 × 3 × 4

First:
2 × 3 = 6
Then:
6 × 4 = 24
Therefore:

2 × 3 × 4 = 24

Changing the Order

The order of numbers in multiplication can change without changing the answer.
Example:

2 × 3 = 6

3 × 2 = 6

Therefore:

2 × 3 = 3 × 2

Grouping Numbers

Example:

2 × 4 × 3

We may calculate:
(2 × 4) × 3
8 × 3 = 24
Or:
2 × (4 × 3)
2 × 12 = 24
The answer remains the same.

More Examples

• 2 × 2 × 3 = 12
• 3 × 2 × 4 = 24
• 5 × 2 × 3 = 30

Word Problem

A classroom has 3 rows of desks. Each row has 4 desks, and 2 pupils sit at each desk.
How many pupils can sit at the desks?

3 × 4 × 2 = 24

There are 24 pupils.

F: LESSON PRESENTATION

F1: Teachers’ Activities

1. Revises multiplication of two numbers.
2. Introduces multiplication of three numbers.
3. Demonstrates taking two factors at a time.
4. Shows that changing the order does not change the answer.
5. Uses counters for practical examples.
6. Gives pupils exercises and simple word problems.

F2: Pupils’ Activities

1. Multiply three one-digit numbers.
2. Group factors in different ways.
3. Change the order of factors.
4. Use counters to solve multiplication problems.
5. Answer simple word problems.

G: CONCLUSION

The teacher revises multiplication of three whole numbers and corrects pupils where necessary.
The teacher reminds pupils to multiply two numbers first before using the third number.

H: EVALUATION GUIDE

Pupils should be able to answer the following questions:

1. Solve: 2 × 3 × 2.
2. Solve: 3 × 4 × 2.
3. Solve: 5 × 2 × 3.
4. Complete: 4 × 3 = 3 × \_\_\_.
5. Does changing the order of factors change the answer?
6. Solve: 2 × 5 × 4.
7. Three boxes contain 2 rows of 4 oranges each. How many oranges are there altogether?