Lesson Note on Revenue Concepts: Meaning, Revenue Schedules and Curves for SS 2

Class: Senior Secondary School 2 (SS2 / SSS2)
Term: 1st Term
Week: 9
Age: 16 years
Duration: 45 minutes
Subject: Economics
Curriculum Theme: Production and Cost Theory
Previous Lesson: Cost Concepts: Short-Run, Long-Run and Views of Cost.
Topic: REVENUE CONCEPTS
Subject Matter: Meaning of revenue (income from sales), total revenue, average revenue, marginal revenue, revenue schedules, revenue curves

Specific Objectives

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

Cognitive Domain:

• Define revenue, total revenue (TR), average revenue (AR), and marginal revenue (MR).
• Explain the formulas for calculating TR, AR, and MR.

Affective Domain:

• Appreciate the importance of revenue concepts in understanding business operations.
• Develop an interest in analyzing market structures through revenue curves.

Psychomotor Domain:

• Construct a revenue schedule from given data.
• Compute TR, AR, and MR from a given schedule or data.
• Sketch and interpret revenue curves.

Social Domain:

• Collaborate with peers to solve problems related to revenue calculations.
• Participate actively in class discussions on revenue concepts.

Reference Materials

The following resources were used in planning this lesson:

• Senior Secondary Schools Education Curriculum
• State Unified Scheme of Work
• A Comprehensive Economics for Senior Secondary Schools by O. F. Anyanwuocha
• https://www.economicshelp.org/microessays/firm/revenue-curves/
• https://www.tutor2u.net/economics/reference/revenue-concepts

Instructional Materials

The teacher will teach this lesson with the aid of:

• Whiteboard and markers or blackboard and chalk
• Charts showing typical revenue schedules
• Diagrams illustrating total, average, and marginal revenue curves
• Calculators

Rationale for the Lesson

Understanding revenue concepts helps pupils grasp how businesses generate income and make decisions about pricing and output. This knowledge is important for analyzing market behavior and understanding economic principles in real-world contexts.

Prerequisite/Previous Knowledge

Pupils have a basic understanding of business, sales, price, and quantity from their previous lessons.

Lesson Content/Board Summary

REVENUE CONCEPTS

Meaning of Revenue

Revenue refers to the total income received by a firm from the sale of its goods and services over a period of time. It is the money obtained from selling a quantity of output.

Total Revenue (TR)

Total Revenue is the total amount of money a firm receives from selling a given quantity of output. It is calculated by multiplying the price per unit of the commodity by the total quantity sold.

Formula: TR = P × Q

• TR = Total Revenue
• P = Price per unit
• Q = Quantity sold

Average Revenue (AR)

Average Revenue is the revenue per unit of output sold. It is obtained by dividing the total revenue by the total quantity sold.

Formula: AR = TR / Q

• AR = Average Revenue
• TR = Total Revenue
• Q = Quantity sold

NOTE: In perfect competition, Average Revenue (AR) is equal to Price (P).

Marginal Revenue (MR)

Marginal Revenue is the additional revenue generated from selling one more unit of output. It is the change in total revenue resulting from a one-unit change in quantity sold.

Formula: MR = ΔTR / ΔQ

• MR = Marginal Revenue
• ΔTR = Change in Total Revenue
• ΔQ = Change in Quantity sold

Revenue Schedule

A revenue schedule is a table showing the relationship between quantity sold and the corresponding total revenue, average revenue, and marginal revenue at different price levels.

Example Revenue Schedule:

Revenue Curves

Revenue curves graphically represent the relationship between output and different types of revenue. Their shapes vary depending on the market structure (e.g., perfect competition, monopoly).

• In imperfect competition (monopoly, monopolistic competition, oligopoly), AR and MR curves slope downwards. The MR curve lies below the AR curve.
• In perfect competition, AR = MR = P, and the curves are horizontal straight lines.

Worked Examples

Example 1: Calculating Revenue Concepts

A firm sells 5 units of a product at N50 per unit. When it increases sales to 6 units, the price falls to N48 per unit. Calculate TR, AR, and MR for both levels of output.

Solution:

For 5 units:

• Step 1: Calculate Total Revenue (TR)

TR = P x Q = N50 x 5 = N250

• Step 2: Calculate Average Revenue (AR)

AR = TR / Q = N250 / 5 = N50

For 6 units:

• Step 1: Calculate Total Revenue (TR)

TR = P x Q = N48 x 6 = N288

• Step 2: Calculate Average Revenue (AR)

AR = TR / Q = N288 / 6 = N48

• Step 3: Calculate Marginal Revenue (MR)

MR = ΔTR / ΔQ = (TR at 6 units – TR at 5 units) / (6 – 5)

MR = (N288 – N250) / 1 = N38 / 1 = N38

Example 2: Interpreting Revenue from a Schedule

Using the revenue schedule provided above, identify the quantity at which Total Revenue is maximized and the corresponding Marginal Revenue.

Solution:

• Step 1: Examine the Total Revenue (TR) column.

TR is maximized at N30.

• Step 2: Identify the quantity corresponding to maximum TR.

Maximum TR (N30) occurs at quantities 5 and 6.

• Step 3: Identify the Marginal Revenue (MR) at this point.

When TR is maximized (i.e., from Q=5 to Q=6), MR is 0.

Teaching Methods/Instructional Techniques

Discussion, Lecture, Demonstration, Question and Answer, Visual Aids

Instructional Procedures

Step 1: Introduction

Time: 5 minutes
Teaching Skill: Set Induction
Teacher’s Activity: The teacher greets the pupils and asks them what they understand by “income” in a business context. The teacher then introduces the topic, “Revenue Concepts,” as the various forms of income a firm earns.
Pupils’ Activity: Pupils respond to the teacher’s questions and listen attentively to the introduction.
Learning Point: Pupils recall prior knowledge and are introduced to the lesson’s topic.

Step 2: Meaning of Revenue

Time: 5 minutes
Teaching Skill: Explanation
Teacher’s Activity: The teacher explains the meaning of revenue as the total income received by a firm from the sale of its goods and services over a period of time.
Pupils’ Activity: Pupils listen, take notes, and ask questions for clarification.
Learning Point: Pupils understand the basic definition of revenue.

Step 3: Total Revenue (TR)

Time: 7 minutes
Teaching Skill: Explanation, Demonstration
Teacher’s Activity: The teacher defines Total Revenue, provides its formula (TR = P × Q), explains each variable, and works through a simple example on the board.
Pupils’ Activity: Pupils copy the definition and formula, and attempt to solve the example with the teacher.
Learning Point: Pupils understand how to calculate Total Revenue.

Step 4: Average Revenue (AR)

Time: 7 minutes
Teaching Skill: Explanation, Demonstration
Teacher’s Activity: The teacher defines Average Revenue, provides its formula (AR = TR / Q), explains each variable, and demonstrates its calculation using the previous example. The teacher also highlights that AR = P.
Pupils’ Activity: Pupils copy the definition and formula, and follow the calculation.
Learning Point: Pupils understand how to calculate Average Revenue and its relationship with price.

Step 5: Marginal Revenue (MR)

Time: 7 minutes
Teaching Skill: Explanation, Demonstration
Teacher’s Activity: The teacher defines Marginal Revenue, provides its formula (MR = ΔTR / ΔQ), explains the concept of change (delta), and demonstrates its calculation using an extended example from the board summary.
Pupils’ Activity: Pupils copy the definition and formula, and engage in the step-by-step calculation.
Learning Point: Pupils understand how to calculate Marginal Revenue and its significance.

Step 6: Revenue Schedules and Curves

Time: 7 minutes
Teaching Skill: Illustration, Guided Practice
Teacher’s Activity: The teacher presents a complete revenue schedule on the board (like the one in the board summary) and explains how each value is derived. The teacher then briefly explains the general shapes of revenue curves for different market structures and encourages pupils to sketch them.
Pupils’ Activity: Pupils copy the revenue schedule, observe the patterns, and attempt to sketch the curves as guided by the teacher.
Learning Point: Pupils learn to construct and interpret revenue schedules and understand the general shapes of revenue curves.

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. Define Total Revenue, Average Revenue, and Marginal Revenue.
2. State the formula for calculating each of the revenue concepts.
3. If a firm sells 10 units at N20 each, and then 11 units at N19 each, calculate the Total Revenue, Average Revenue, and Marginal Revenue for the 11th unit.
4. Describe the relationship between Total Revenue and Marginal Revenue when Total Revenue is maximized.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 2 minutes
Teaching Skill: Summarization
Teacher’s Activity: The teacher summarizes the key points of the lesson, emphasizing the importance of understanding revenue for business analysis. The teacher then assigns homework: “Draw a typical revenue curve for a firm operating in imperfect competition and label the curves.”
Pupils’ Activity: Pupils listen to the summary and copy the homework assignment.
Learning Point: Pupils reinforce their understanding and are given an opportunity for further practice.

Lesson Keywords

• Revenue – The total income a firm receives from selling its goods and services.
• Total Revenue (TR) – The total amount of money from selling a specific quantity of output.
• Average Revenue (AR) – Revenue per unit of output sold.
• Marginal Revenue (MR) – The additional revenue from selling one more unit of output.
• Revenue Schedule – A table showing the relationship between quantity sold and various revenue figures.
• Revenue Curve – A graphical representation of the relationship between output and revenue.

Differentiation

For pupils who grasp concepts quickly, the teacher can provide additional complex problems involving changes in price elasticity of demand and its effect on revenue. For pupils requiring more support, the teacher will provide simplified schedules and guide them through step-by-step calculations, focusing on one concept at a time.

Note for teachers using this lesson plan

Ensure that pupils clearly understand the distinction between total, average, and marginal concepts. Emphasize the practical application of these concepts in business decision-making. Encourage drawing and labeling of curves as it helps in visual understanding. Use real-life examples of businesses and their sales to make the topic relatable.