Ratio and Percentages (Primary 5)

 

MATHEMATICS

SECOND TERM 

WEEK 1 

PRIMARY 5 

THEME – NUMBER AND NUMERATION 

 PREVIOUS LESSON – First Term Examination Links For Primary Schools

TOPIC – RATIO AND PERCENTAGES 

LEARNING AREA

1. Introduction to Ratio

2. Ratio in its Lowest

3. Percentages

4. Word problems

 

PERFORMANCE OBJECTIVES 

By the end of the lesson, the pupils should have attained the following objectives (cognitive, affective and psychomotor) and should be able to –

1. recognise the idea of ratio.

2. simplify ratio in its lowest term.

3. express numbers as a percentage of another.

4. solve problems involving ratio.

 

ENTRY BEHAVIOUR

Comparisons

 

INSTRUCTIONAL MATERIALS

The teacher will teach the lesson with the aid of:

1. Number of pupils in the class.

2. Different shapes with different colors

 

 

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

1. Scheme of Work

2. 9 – Years Basic Education Curriculum

3. Course Book

4. All Relevant Material

5. Online Information

 

CONTENT OF THE LESSON  

LESSON 1 – INTRODUCTION 

Teacher’s/Pupil’s Activities 1 – Ask a boy to count the number of boys in the class and the girls to do the same. Then, note the results on the board. 

For example,

Boys – 24

Girls – 30

 

Pupil’s Activities 2 – Ask them to compare the number of boys and girls together. 

The number of girls is more than the number of boys.

Boys < girls

Girls > boys

 

Teacher’s remark – Comparing the number of boys and girls together is called ratio. A ratio is a way to show a relationship or compare two numbers of the same kind. Ratio is use ratios to compare things of the same type.

The ratio of boys and girls is written as

1. boys : girls, this means ratio of boys to girls 

2. girls : boys, this means ratio of girls to boys. 

 

Teacher’s Activities 3A – Group the pupils in 3 groups 

Group 1 – Circles

Group 2 – Triangles 

Group 3 – Squares

 

Groups Activities 3B – Identify the objects and colors on the chart. 

 

 

Group 1

Circles – 4 Greens, 5 Blues, 7 Reds and 3 Yellows

 

Group 2

Triangles – 4 Greens, 3 Blue, 3 Reds and 3 Yellows

 

Group 3

Squares – 6 Greens, 3 Blues, 4 Reds and 3 Yellows

 

Pupil’s Activities 4 – Express the ratio of greens to reds and yellows to blues 

Group 1 – Circle 

1. Greens :  Reds = 3 : 7

2. Yellows : Blues = 3 : 4

 

Group 2 – Triangles

1. Greens :  Reds = 4 : 3

2. Yellows : Blues = 3 : 3

 

Group 3 – Squares

1. Greens :  Reds = 4 : 3

2. Yellows : Blues = 3 : 3

 

Pupil’s Activities 5 – Class Exercises/Assignments 

Express the ratio of Diamond to Space and Heart to Space. 

Diamond – ♦♦♦♦♦♦♦♦

Heart – ♥♥♥

Space – ♠♠♠♠

Club – ♣♣♣♣♣

 

 

LESSON 2 – EXPRESS RATIO IN SIMPLEST FORM

Teacher’s/Pupil’s Activities 1 – Guide the Pupils Express Ration as  Fractions 

Ratio can be expressed as fractions.

 

Express the following ratio as fractions – 

1. Diamond to Space

= 8 : 4

= 8/4

 

2. Heart to Club 

= 3 : 5

= 3/5

 

3. Club to Heart 

= 5 : 3

=.5/3

 

4. Heart to Diamond 

= 3 : 8

= 3/8

 

Pupil’s Activities 2  – Ratio in Its Simplest form 

Find the missing number –

1. 5 : 15 = 1 : 3

2. 8 : 6 = 4 : 3

3. 14 : 16 = 7 : 8

 

Teacher’s Activities 3 – Randomly ask the pupils how the questions are solved. 

 

1. 5 : 15

= 5 : 15

= 1 x 5 : 5 x 3

= 1 : 3

 

2. 8 : 6

= 4 x 2 : 2 : 3

= 4 : 3

 

3. 14 : 16

= 7 x 2 : 2 x 8

= 7 : 8

 

Teacher’s remark – You are all right and correct. This working is called Ratio in Its Simplest form. You can also express the ratio as fractions, then simply.

That’s,

14 : 16

= 14/16 

= (7 x 2)/(8 x 2)

= 7/8

 

Pupil’s Activities 4 – Class Exercises/Assignments 

Express the following as ratio of one another in their simplest form, 

1. 5 as a ratio of 15

2. 8 as a ratio of 64

3. 9 as a ratio of 27

 

LESSON 3 – QUANTITATIVE REASONINGS ON RATIO

As stated in their quantitative books and textbooks. 

 

 

LESSON 4 – PERCENTAGES

Teacher’s/Pupil’s Activities 1 – Guide pupils to express ratio as percentage 

Express the following ratio as percentage,

1. 4 : 5

2. 7 : 8

Step 1 – Express ratio as fractions.

1. 4 : 5

= 4/5

 

Step 2 – Multiple the fractions by 100.

= 4/5 x 100

 

Step 3 – Simply in its lowest form.

= (4 x 100)/5

= (4 x 20 x 5)/5

= 4 x 20

= 80%

 

Follow the same procedure for the second question.

 

Teacher’s remark – The above procedure is expressing ratio as percentage. Percent means per 100. 80% means 80 out 100. 80% is pronounced as 80 percent. 80% can also be written as 80/100 (fraction).

This symbol (%) is used as percentage meaning 100. 

 

Pupil’s Activities 2 – Class Exercises/Assignments 

Express the following ratio as percentage,

1. 24 : 30

2. 6 :  18

3. 45 : 15

 

Relevant Lesson on Percentage, follow the link – Simple Problems on Percentages (Primary 5 and Primary 6)

 

LESSON 5 – QUANTITATIVE REASONING ON PERCENTAGES

As stated in their quantitative books or textbooks. 

 

 

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. Leads pupils to compare things using ratio.

Pupil’s Activities – Express things that are alike as ratio of another.

3. Asks pupils to solve quantitative problems on ratio.

Pupil’s Activities – solve quantitative problems on ratio.

4. Guides pupils to express ratio as percentage.

Pupil’s Activities – Follow the teacher’s instructions.

 

CONCLUSION

• To conclude the lesson for the week, the teacher revises the entire lesson and links it to the following week’s lesson.

• Next Lesson –

 

LESSON EVALUATION 

Pupils to:

1. recognise the idea of ratio.

2. simplify ratio in its lowest term.

3. express numbers as a percentage of another.

4. solve problems involving ratio.