Money : Conversion, Addition, Subtraction and Commercial Arithmetic (Profit and Loss)

SECOND TERM E NOTES FOR PRIMARY 4 MATHEMATICS

SUBJECT: MATHEMATICS

CLASS: BASIC FOUR / / PRIMARY 4

WEEK 8

TOPIC: Money : Conversion, Addition, Subtraction and Commercial Arithmetic (Profit and Loss) 

Importance

• It is used in obtaining the
  basic necessities of life
  including food, clothing
  and shelter.
• It is also used for foreign
  exchange.

Learning Objectives

• Pupils should be able to:
  convert naira to kobo and
  vice versa.
• calculate the sum and
  difference of money.
  differentiate between profit
  and loss.
• solve real life problems on
  profit and loss.
• solve quantitative Reasoning
  on money.
• To define the concepts of profit and loss
• To explain the differences between profit and loss
• To provide examples of profit and loss in Nigerian money
• To develop basic skills in calculating profit and loss

Learning Activities

• Pupils as a class dramatize classroom sales by
  using their books, writing materials, school
  bags, lunch box etc as commodities.
• They decide upon how much each item will be sold
  and create fun price tags to be placed on the items.
• Once the items are labeled, tagged and
  in place, set up a play cash register and then start shopping. One of them is given a small
  purse of dummy money and allow them to take tums in shopping for an item.
• One of the pupils
  to be at the cash register.

Embedded Core Skills

• Critical thinking and problem solving skills
• Communication and Collaboration
• Student Leadership skills and Personal Development
• Creativity and Imagination

Audio Visual Resource

• Books
• Writing materials
• School bags
• Lunch bags / box
• Water bottles

Content

Nigeria’s official currency is the Naira (₦), and one Naira is divided into 100 kobo. This means that 100 kobo make up one Naira.

To convert from Naira to kobo, you simply need to multiply the amount of Naira by 100. For example, if you have 3 Naira, you would multiply 3 by 100, which equals 300 kobo. So, 3 Naira is the same as 300 kobo.

To convert from kobo to Naira, you divide the amount of kobo by 100. For example, if you have 500 kobo, you would divide 500 by 100, which equals 5 Naira. So, 500 kobo is the same as 5 Naira.

Here’s a simple example:

Let’s say you have 50 kobo and you want to know how much it is in Naira.

To convert kobo to Naira, you divide by 100. So, 50 kobo divided by 100 equals 0.50 Naira. Therefore, 50 kobo is equal to 0.50 Naira.

Similarly, let’s say you have 3 Naira and you want to know how much it is in kobo.

To convert Naira to kobo, you multiply by 100. So, 3 Naira multiplied by 100 equals 300 kobo. Therefore, 3 Naira is equal to 300 kobo.

Money

Addition of money

Convert money from one unit to another

Shop and collect the correct change

Add money

Subtract money

Solve word problems involving money.

CONVERSION INVOLVING UNITS OF MONEY

Note

100 k = 􀎏1.00

When changing kobo to Naira we divide the given amount by 100.

Examples

1. 520k = 520/100 = 􀎏5.20k 2. 890k = 890/100 = 􀎏8.90k

= 􀎏5.20 = 􀎏8.90

Exercise 1

Convert the following to Naira.

1. 638k = 2. 750k = 3. 430k = 4. 970k = 5. 257k =

6. 1 008k = 7. 3 450k = 8. 1 520 = 9. 17 000k = 10. 28 640k =

Examples

When converting Naira to kobo, we multiply by 100.

1. 􀎏8.00 = 8 × 100 = 800k 2. 􀎏17.50 = 17.50 × 100 = 1750k

or 􀎏8.00 = 800k

Example: find the sum of N4.36, N3.79 and N4.82

N K

4. 36

+ 3. 7 9

+ 4. 8 2

12. 9 7

EXERCISES

Add up

1. N56.00, N24.70 and N32.55
2. N32.20, N174.30 and N132.30
3. N91.00, N152.10 and N184.20
4. N241.80, N378.35 and N29.46
5. Fin the sum, of N168.00 and N276.00
6. Find the sum of N128.10, N78.30 and N8.05
7. I have N1000 in my pocket and my father gave me N174.20 more. How much do I have altogether?

Subtraction of money

Example 1

What is the difference between N167.50 and N345.00?

N K

345.00

-167. 50

177.50

EXERCISE 2

1. Find the difference between N406.60 and N322.20
2. Find the different between N270 and N162.30
3. Subtract N236.44 from N475.00
4. I have N150.00 and I bought a spoon for N85. How much is my change?
5. How much more is N147.50 greater than N112.80
6. How much more is N36.00 than N278.00

Evaluation

1. How many kobo make up one Naira? a. 10 kobo b. 50 kobo c. 100 kobo d. 500 kobo
2. If you have 200 kobo, how much Naira do you have? a. 0.2 Naira b. 2 Naira c. 20 Naira d. 200 Naira
3. How much kobo is equivalent to 5 Naira? a. 5 kobo b. 50 kobo c. 500 kobo d. 5,000 kobo
4. If you have 3 Naira, how many kobo do you have? a. 0.3 kobo b. 3 kobo c. 30 kobo d. 300 kobo
5. How many Naira is equivalent to 250 kobo? a. 0.25 Naira b. 2.5 Naira c. 25 Naira d. 250 Naira
6. If you have 4,500 kobo, how much Naira do you have? a. 4.5 Naira b. 45 Naira c. 450 Naira d. 4,500 Naira
7. How many kobo is equivalent to 7 Naira? a. 0.07 kobo b. 0.7 kobo c. 7 kobo d. 700 kobo
8. If you have 2 Naira, how many kobo do you have? a. 0.02 kobo b. 0.2 kobo c. 20 kobo d. 200 kobo
9. How much Naira is equivalent to 1,200 kobo? a. 0.12 Naira b. 1.2 Naira c. 12 Naira d. 120 Naira
10. If you have 1,500 Naira, how many kobo do you have? a. 150 kobo b. 1,500 kobo c. 15,000 kobo d. 150,000 kobo

Addition and subtraction of Money In Naira and Kobo

To add or subtract money in Nigeria, we first need to understand that the value of money is determined by the numbers of Naira and kobo that it has.

Let’s take an example. Suppose you want to add 50 Naira and 75 kobo to 25 Naira and 50 kobo. Here’s how you can do it:

Addition:

1. Add the Naira amounts together: 50 Naira + 25 Naira = 75 Naira
2. Add the kobo amounts together: 75 kobo + 50 kobo = 125 kobo
3. Simplify the kobo amount by converting any additional kobo to Naira: since 125 kobo is more than 100, we can convert 100 kobo into 1 Naira and the remaining 25 kobo will be added. So, we have 75 Naira and 25 kobo.

So, the answer is 75 Naira and 25 kobo.

Subtraction:

Now let’s take another example, suppose you want to subtract 30 Naira and 60 kobo from 50 Naira and 75 kobo. Here’s how you can do it:

1. First, subtract the Naira amounts: 50 Naira – 30 Naira = 20 Naira
2. Then, subtract the kobo amounts: 75 kobo – 60 kobo = 15 kobo
3. Simplify the kobo amount by converting any negative kobo to Naira: since we cannot have negative kobo, we convert 1 Naira to 100 kobo and add 100 kobo to 15 kobo. So, we have 19 Naira and 15 kobo.

So, the answer is 19 Naira and 15 kobo.

It is important to remember that when adding or subtracting money in Naira and kobo, we first add or subtract the Naira amounts and then the kobo amounts. If the total kobo is more than 100, we simplify by converting it to Naira. If the kobo is negative, we convert 1 Naira to 100 kobo and add it to the kobo amount.

Evaluation

1. What is the value of ₦35:25 plus ₦20:50? a. ₦55:75 b. ₦50:75 c. ₦55:50 d. ₦55:25
2. What is the value of ₦55:60 minus ₦30:20? a. ₦25:40 b. ₦35:40 c. ₦25:80 d. ₦35:80
3. What is the value of ₦25:40 plus ₦15:50? a. ₦40:90 b. ₦40:90 c. ₦40:10 d. ₦40:25
4. What is the value of ₦40:70 minus ₦25:40? a. ₦15:30 b. ₦15:90 c. ₦15:80 d. ₦15:35
5. What is the value of ₦60:30 plus ₦25:50? a. ₦85:80 b. ₦85:20 c. ₦85:50 d. ₦85:70
6. What is the value of ₦50:80 minus ₦25:60? a. ₦25:20 b. ₦25:40 c. ₦25:80 d. ₦25:50
7. What is the value of ₦45:70 plus ₦15:20? a. ₦60:90 b. ₦60:80 c. ₦60:10 d. ₦60:40
8. What is the value of ₦80:90 minus ₦45:70? a. ₦35:20 b. ₦35:30 c. ₦35:80 d. ₦35:10
9. What is the value of ₦55:30 plus ₦25:80? a. ₦81:10 b. ₦81:50 c. ₦81:70 d. ₦81:60
10. What is the value of ₦75:60 minus ₦50:80? a. ₦24:80 b. ₦24:90 c. ₦24:20 d. ₦24:70

Differences Between Profit and Loss

When we talk about profit and loss, we are usually referring to a situation where someone has sold something and made money or lost money as a result. Let’s take an example to explain it further.

Suppose you have a small business selling candy, and you bought a bag of candy for ₦500. You then sold all the candy for ₦700. We can use these numbers to calculate whether you made a profit or a loss.

Profit:

To calculate the profit, we subtract the cost of buying the candy from the money received for selling the candy. So, in this case, the profit is:

₦700 (money received for selling candy) – ₦500 (cost of buying candy) = ₦200 (profit)

So, you made a profit of ₦200. This means you earned more money than you spent on buying the candy.

Loss:

On the other hand, if you sold the candy for less than you bought it, you would have a loss. Let’s take an example. Suppose you bought a bag of candy for ₦500, but you were only able to sell it for ₦400. We can use these numbers to calculate whether you made a profit or a loss.

To calculate the loss, we subtract the money received for selling the candy from the cost of buying the candy. So, in this case, the loss is:

₦400 (money received for selling candy) – ₦500 (cost of buying candy) = ₦100 (loss)

So, you made a loss of ₦100. This means you lost money because you spent more money buying the candy than you earned from selling it.

To summarize, profit means earning more money than you spent, while loss means spending more money than you earned. It is important to keep track of profits and losses in business to know if you are making a profit or a loss

Evaluation

1. What does it mean to make a profit? a. Earning less money than you spent b. Earning more money than you spent c. Spending all the money you earned d. Spending some of the money you earned
2. What does it mean to make a loss? a. Earning less money than you spent b. Earning more money than you spent c. Spending all the money you earned d. Spending some of the money you earned
3. If you buy a toy for ₦100 and sell it for ₦150, did you make a profit or a loss? a. Profit b. Loss c. Neither d. Both
4. If you buy a pencil for ₦20 and sell it for ₦15, did you make a profit or a loss? a. Profit b. Loss c. Neither d. Both
5. If you buy a shirt for ₦500 and sell it for ₦700, how much profit did you make? a. ₦100 b. ₦200 c. ₦300 d. ₦400
6. If you buy a bag of rice for ₦1,000 and sell it for ₦900, how much loss did you make? a. ₦50 b. ₦100 c. ₦200 d. ₦300
7. If you buy a book for ₦500 and sell it for ₦500, did you make a profit or a loss? a. Profit b. Loss c. Neither d. Both
8. If you buy a phone for ₦20,000 and sell it for ₦25,000, how much profit did you make? a. ₦5,000 b. ₦10,000 c. ₦15,000 d. ₦20,000
9. If you buy a pair of shoes for ₦2,000 and sell it for ₦1,500, how much loss did you make? a. ₦250 b. ₦500 c. ₦1,000 d. ₦1,500
10. If you buy a bicycle for ₦10,000 and sell it for ₦15,000, did you make a profit or a loss? a. Profit b. Loss c. Neither d. Both

Lesson Presentation

Introduction:

• Begin by asking students if they have ever heard of the terms “profit” and “loss.”
• Ask students if they know what these terms mean.
• Define the terms “profit” and “loss” and give examples in a relatable context (e.g. selling candy, buying toys, etc.).
• Explain that these terms are used in businesses to determine how much money is being made or lost.

Lesson Body:

• Use the whiteboard or chalkboard to write the definitions of profit and loss.
• Provide more detailed examples of profit and loss in Nigerian money.
• Demonstrate how to calculate profit and loss using simple equations, and have students practice calculating profit and loss using examples.
• Provide more advanced examples of profit and loss, and challenge students to calculate the profit or loss on their own.
• Discuss the importance of keeping track of profit and loss in business, and the consequences of not doing so.

Conclusion:

• Review the concepts of profit and loss, and have students share their own examples or experiences of making a profit or loss.
• Ask students to complete a worksheet to reinforce their understanding of profit and loss.
• Encourage students to keep track of their own profits and losses in everyday life (e.g. selling lemonade, buying and selling toys), and to share their results with the class in future lessons.

Assessment:

• Monitor students’ progress throughout the lesson through observation and questioning.
• Use the worksheets completed by students to assess their understanding of the concepts of profit and loss.
• Provide feedback to students on their progress, and address any areas where students may need additional support.

Weekly Assessment /Test

1. Profit means earning _______ money than you spent.
2. Loss means spending _______ money than you earned.
3. To calculate profit, we subtract the cost of buying something from the money received for _______ it.
4. To calculate loss, we subtract the money received for selling something from the cost of _______ it.
5. If you buy an item for ₦100 and sell it for ₦150, you make a _______ of ₦_______.
6. If you buy an item for ₦200 and sell it for ₦150, you make a _______ of ₦_______.
7. If you buy an item for ₦300 and sell it for ₦250, you make a _______ of ₦_______.
8. If you buy an item for ₦100 and sell it for ₦50, you make a _______ of ₦_______.
9. If you buy an item for ₦500 and sell it for ₦400, you make a _______ of ₦_______.
10. If you buy an item for ₦1,000 and sell it for ₦900, you make a _______ of ₦_______