Area of Rectangles, Length × Breadth and Quantitative Reasoning for Primary 4

Class: Primary 4
Term: Third Term
Week: 6
Age: 9 years
Duration: 45 minutes
Subject: General Mathematics
Curriculum Theme: Mensuration
Focal competence: Calculating the surface area of a rectangle and a given rectangular farmland
Key competencies/values: Collaboration
Skills:

• find area of rectangles using the formula
• calculate the area of rectangular farmland in the environment
• solve problems on quantitative aptitude related to areas of rectangle

Previous Lesson: Use of A.M. and P.M., Quantitative Aptitude Problems Involving Time
Topic: Area
Subject Matter: Meaning of area, Area of rectangles, applying length × breadth to rectangular surfaces/farmland, quantitative reasoning

Specific Objectives

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

Cognitive Domain

• explain the meaning of area;
• find the area of rectangles using the formula;
• solve problems on quantitative aptitude related to areas of rectangle.

Psychomotor Domain

• calculate the area of rectangular farmland in the environment.

Reference Materials

The following resources were used in planning this lesson:

• 2025 Revised 9 Years Basic Education Curriculum
• Relevant State Unified Scheme of Work
• Primary Mathematics for Nigerian Schools, Book 4
• The HeadTeacher Scheme of work

Instructional Materials

The teacher will teach this lesson with the aid of:

• Cardboard sheet
• Square chart/squared paper
• Ruler
• Rectangular objects (e.g., textbook, desktop, exercise book)
• Pictures of farmland

Rationale for the Lesson

Understanding area is fundamental for measuring surfaces in everyday life, from determining the size of a room to calculating the amount of paint needed for a wall. This lesson equips pupils with the skill to calculate the area of rectangular shapes, which is a practical application in various fields, including agriculture and construction. It also develops their problem-solving abilities through quantitative reasoning.

Prerequisite/Previous Knowledge

Pupils should be familiar with basic shapes like rectangles and squares, understand the concepts of length and breadth, and be able to perform multiplication.

Lesson Content/Board Summary

Area

Meaning of Area

Area is the amount of surface covered by a flat shape or object. It tells us how much space a two-dimensional shape takes up.

Square Units

Area is measured in square units. This is because we are measuring how many small squares can fit inside a shape. Common square units include:

1. Square centimetres (cm²)
2. Square metres (m²)
3. Square kilometres (km²)

Area of a Rectangle

The area of a rectangle is found by multiplying its length by its breadth (or width).

Formula

( text{Area} = text{Length} times text{Breadth} )

Where:

1. (text{Length}) = the longer side of the rectangle
2. (text{Breadth}) = the shorter side of the rectangle

Example 1

Question: Find the area of a rectangle with a length of 8 cm and a breadth of 5 cm.

Solution:

Step 1: Write the formula.

( text{Area} = text{Length} times text{Breadth} )

Step 2: Substitute the values.

( text{Area} = 8 text{ cm} times 5 text{ cm} )

Step 3: Simplify and write the answer.

( text{Area} = 40 text{ cm}^2 )

Answer: ( 40 text{ cm}^2 )

Example 2

Question: A rectangular farmland is 20 metres long and 15 metres wide. What is its area?

Solution:

Step 1: Write the formula.

( text{Area} = text{Length} times text{Breadth} )

Step 2: Substitute the values.

( text{Area} = 20 text{ m} times 15 text{ m} )

Step 3: Simplify and write the answer.

( text{Area} = 300 text{ m}^2 )

Answer: ( 300 text{ m}^2 )

Quantitative Reasoning (Area)

Quantitative reasoning problems often involve using the area formula to find a missing side or comparing areas. For example, if the area of a rectangle is 24 cm² and its length is 6 cm, the breadth can be found by dividing the area by the length ((24 text{ cm}^2 div 6 text{ cm} = 4 text{ cm})).

Teaching Methods/Instructional Techniques

Discussion, Demonstration, Guided Practice, Question and Answer, Explanation, Problem Solving, Individual Practice

Instructional Procedures

Step 1: Introduction

Time: 5 minutes

Teaching Skill: Explaining/Questioning

Teacher’s Activity: The teacher asks pupils to identify flat surfaces in the classroom (e.g., desktop, floor, wall). The teacher then asks how they would describe the “size” of these surfaces.

Pupils’ Activity: Pupils identify surfaces and discuss how to describe their sizes.

Learning Point: Covering surfaces

Step 2: Meaning of Area and Square Units

Time: 7 minutes

Teaching Skill: Demonstration/Explanation

Teacher’s Activity: The teacher uses a square chart or squared paper to demonstrate how squares can cover a surface. The teacher explains that the number of squares used is the “area” and that area is measured in “square units” (cm², m²). The teacher defines area.

Pupils’ Activity: Pupils observe the demonstration and listen to the explanation. They repeat the definition of area and square units.

Learning Point: Concept of area

Step 3: Deriving and Applying the Area of Rectangle Formula

Time: 7 minutes

Teaching Skill: Guided Discovery/Explanation

Teacher’s Activity: The teacher uses a rectangular object (e.g., textbook) and a ruler to measure its length and breadth. The teacher guides pupils to count the squares on squared paper covering a rectangle and relate it to multiplying length by breadth to derive the formula: Area = Length × Breadth.

Pupils’ Activity: Pupils observe, participate in counting squares, and state the formula for the area of a rectangle.

Learning Point: Rectangle area formula

Step 4: Worked Example 1 (Direct Calculation)

Time: 7 minutes

Teaching Skill: Modelling/Guided Practice

Teacher’s Activity: The teacher presents Example 1 from the Board Summary and guides pupils through the step-by-step solution on the board, emphasizing the formula and correct units.

Pupils’ Activity: Pupils follow the teacher’s steps, copy the example, and participate in solving it.

Learning Point: Calculating rectangle area

Step 5: Worked Example 2 (Farmland Application)

Time: 7 minutes

Teaching Skill: Application/Problem Solving

Teacher’s Activity: The teacher presents Example 2 (farmland problem) and guides pupils to apply the formula to a real-world scenario. The teacher may show a picture of farmland to make it concrete.

Pupils’ Activity: Pupils solve the farmland area problem with guidance and ask questions for clarification.

Learning Point: Farmland area calculation

Step 6: Quantitative Reasoning Introduction

Time: 5 minutes

Teaching Skill: Problem Solving/Analysis

Teacher’s Activity: The teacher introduces a simple quantitative reasoning problem related to area, such as finding a missing side given the area and one side. The teacher guides pupils on how to approach such problems (e.g., using division).

Pupils’ Activity: Pupils attempt to solve the quantitative reasoning problem and discuss their approaches.

Learning Point: Area problem solving

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

1. What is area?
2. What are the units for measuring area?
3. State the formula for finding the area of a rectangle.
4. A rectangular table top is 100 cm long and 60 cm wide. Calculate its area.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Area calculation assessment

Step 8: Note-Taking

Time: 4 minutes

Teaching Skill: Guided Writing

Teacher’s Activity: The teacher guides pupils to copy the essential Board Summary notes on the meaning of area, square units, and the area of a rectangle formula with examples into their notebooks.

Pupils’ Activity: Pupils copy the notes carefully into their notebooks.

Learning Point: Copying area notes

Step 9: Conclusion

Time: 3 minutes

Teaching Skill: Summarising

Teacher’s Activity: The teacher briefly reminds pupils that area is the space covered by a flat surface and is calculated by multiplying length by breadth for rectangles. The teacher encourages them to look for rectangular shapes around them and imagine calculating their areas.

Pupils’ Activity: Pupils listen and confirm their understanding.

Learning Point: Area concept reinforced

Continuous Assessment/Further Study

Type: Homework

Instruction: Solve the following problems in your mathematics notebook:

1. Define area in your own words.
2. What is the area of a rectangular classroom that is 9 metres long and 7 metres wide?
3. A mat has an area of 120 cm². If its breadth is 10 cm, what is its length?
4. Draw a rectangle and label its length as 6 cm and breadth as 4 cm. Then calculate its area.

Lesson Keywords

• Area – The amount of surface covered by a flat shape.
• Length – The measurement of the longest side of a rectangle.
• Breadth – The measurement of the shorter side of a rectangle.
• Rectangle – A four-sided shape with four right angles and opposite sides equal.
• Square Units – Units used to measure area, such as cm² or m².

Differentiation

For weaker learners, provide pre-drawn rectangles on squared paper for them to count squares directly before applying the formula. For faster learners, introduce more complex word problems involving finding missing sides or comparing the areas of two different rectangles.

Suggested Lesson Videos

For further understanding, search on YouTube for: area of rectangle primary 4 nigeria

Teacher Guide for Using This Lesson Plan

Before the lesson, ensure you have a variety of rectangular objects, a ruler, and squared paper for demonstration. Start by engaging pupils with familiar objects to introduce the concept of surface coverage. Guide them clearly through the derivation of the area formula, allowing them to participate in counting squares to make the concept concrete. Emphasize the importance of square units. When working through examples, encourage pupils to state the formula first before substituting values. For the farmland example, use a picture or describe a local farm to make it relatable. Encourage collaboration during guided practice. During note-taking, ensure pupils copy the Board Summary accurately. Pay attention to common errors such as confusing area with perimeter or forgetting to use square units. Provide extra support for pupils struggling with multiplication or conceptual understanding, and offer challenging problems for those who grasp the concept quickly.