Simple Problems on Percentages (Primary 5 and Primary 6)
MATHEMATICS
FIRST TERM/FIRST/WEEK/PRIMARY 6
SECOND TERM/WEEK 2/PRIMARY 5
THEME: NUMBER AND NUMERATION
TOPIC: PERCENTAGES
Percentage means quantities divided into hundred parts.
PERFORMANCE OBJECTIVES
By the end of the lesson, the pupils should have attained the following objectives (cognitive, affective and psychomotor) and be able to:
1. recognise the idea (meaning) of percentages;
2. express numbers as a percentage of other numbers;
3. solve problems on percentage increase;
4. solve problems on percentage decrease;
5. find percentages of quantities
ENTRY BEHAVIOR
The pupils are required to already have learned ratio and proportions.
INSTRUCTIONAL MATERIALS
The teacher will teach the lesson with the aid of:
1. Source for correct data on HIV/AIDS.
2. Data chart on HIV/AIDS.
3. Charts with population figures.
METHOD OF TEACHING – Choose a suitable and appropriate methods for the lessons.
Note – Irrespective of choosing methods of teaching, always introduce an activities that will arouse pupil’s interest or lead them to the lessons.
REFERENCE MATERIALS
Scheme of Work
9 – Years Basic Education Curriculum
New Methods Mathematics Book 6
Champion Mathematics Book 6
All Relevant Material
Online Information
CONTENT OF THE LESSON
LESSON ONE – IDEA OF PERCENTAGE
Group’s/Pupil’s Activities 1 – Count the number of spaces on the chart
Total number of spaces is 100.
Group 1 – Count the shaded and unshaped parts
Shaped parts, _____ and unshaded parts _____.
Group 2 – Count the shaded and unshaped parts
Shaped parts, _____ and unshaded parts _____.
Group 3 – Count the shaded and unshaped parts
Shaped parts, _____ and unshaded parts _____.
Teacher’s remark – Percentage means quantities divided into hundred parts. Each of the space presents a percentage. 2 spaces represent 2 percent and it’s written as 2% or 2/100 (as known as fraction) . This symbol (%) represents percentage.
Pupil’s Activities 2 – Express the shaped and unshaded parts as percentage and fraction.
Group 1,
Shaded parts is 35% or 35/100
Unshaded parts is 65% or 65/100
The same goes for group 2 and 3.
Pupil’s Exercises/Assignments
Write these percentages aw fractions.
1. 70%
2. 54%
3. 18%
4. 25%
5. 44%
Write these fractions as percentages.
6. 51/100
7. 72/100
8. 42/100
9. 185/100
10. 1725/100
LESSON TWO – EXPRESSING NUMBER OR QUANTITY AS A PERCENTAGE OF ANOTHER
Teacher’s Activities – Guides pupils to follow the steps below when a number or quantity is to be expressed as a percentage of another.
Teacher’s/Pupil’s Activities 1 – Express 40 as percentage of 80.
= 40/80 x 100
= 1/2 x 100
= 100/2
= 50%
Pupil’s Activities 2 – Express 20 as percentage of 50.
= 20/50 x 100
= 2/5 x 100
= 2 x 20
= 40%
Pupil’s Exercises/Assignments
Express the first quantity as a percentage of the second:
1. 15 to 20
2. 18 months to 24 months.
3. 25 out of 100.
LESSON THREE – PERCENTAGE INCREASE (ADDITION) AND DECREASE (SUBTRACTION)
- Percentage increase
Teacher’s Activities – Guides pupils to follow the steps below when working on percentage increases or decrease.
Teacher’s/Pupil’s Activities 1 – Increase ₦15 000 by 10%
10% = 10/100
= ₦15 000 x 10/100
= ₦150 x 10
= ₦1500
10% increase is ₦15 000 + ₦1500
= ₦16 000.
Teacher’s remark – You add, if it’s percentage increase and subtract, if it’s percent decrease.
Teacher’s/Pupil’s Activities 2 – Decrease ₦15 000 by 20%
20% = 20/10
Therefore,
= ₦15 000 x 20/100
= ₦150 x 20
= ₦3 000
20% decrease is ₦15 000 – ₦3 000
= ₦12 000.
Pupil’s Exercises/Assignments
1. Increase ₦6 000 by 15%.
2. A new laptop cost ₦50, 000 is decreased by 10%. What is the new price?
Lesson 4 is For Primary 6
LESSON FOUR – WORD PROBLEMS ON PROPORTION
Teacher’s Activities – Guides pupils to follow the steps below when working on proportion.
Teacher’s/Pupil’s Activities 1
- Mr. Ola buys 50 bags of rice every month. If he plans to increase the quantity by 30%, how many bags will he buy?
30% = 30/10
Therefore,
= 50 x 30/100
= 5 x 3
= 15
30% increase is 50 + 15
= 65 bags.
Teacher’s/Pupil’s Activities 2
- A man bought a carton of milo at ₦5 500, 3 months ago. When she went again to the market to buy another carton, he discovered that the price has decreased by 15%. How much is the present price?
15% = 15/100
Therefore,
= ₦5 500 x 15/100
= ₦55 x 15
= ₦825
15% decrease is ₦5 500 + ₦825
= ₦6 325
Pupil’s Exercises/Assignments
- Transport fare was increased from ₦40 to ₦350, what is the percentage increase.
- House rent is ₦60 000 per annum. What rent must be charged to give 25% decrease?
PRESENTATION
To deliver the lesson, the teacher adopts the following steps:
1. To introduce the lesson, the teacher revises the previous lesson. Based on this, he/she asks the pupils some questions;
2. Guides pupils to express numbers as a percentage of another;
Pupil’s Activities – Express numbers as a percentage of another.
3. Guides pupils to calculate numbers expressed as a percentage of another;
Pupil’s Activities – Calculate numbers expressed as a percentage of another.
4. Guides pupils to calculate percentage increase and decrease;
5. Guides pupils to solve problems on percentage increase and decrease;
Pupil’s Activities – Solve problems on percentage increase and decrease.
6. Guides pupils to give more examples of everyday activities where percentage increase and decrease is needed;
Pupil’s Activities – Gives examples of everyday activities that require percentage increase.
7. Guides pupils to solve problems in quantitative aptitude on percentage increase or decrease.
Pupil’s Activities – Solves quantitative aptitude on percentage decrease.
CONCLUSION
- To conclude the lesson for the week, the teacher revises the entire lesson and links it to the following week’s lesson.
LESSON EVALUATION
Pupils to:
1. express given numbers as a percentage of another;
2. calculate given numbers expresses as a percentage of another;
3. calculate percentage increase of a given population growth;
4. calculate percentage decrease of a given population growth;
5. solves quantitative aptitude on percentage increase and decrease.