# Weight – Addition, Subtraction, Multiplication and Division Involving Grams, Kilograms and Tonnes (Primary 6)

MATHEMATICS

SECOND TERM

WEEK 8

PRIMARY 6

THEME – MEASUREMENTS

PREVIOUS LESSON – Second Term Scheme of Work and Plan Lesson Notes for MATHEMATICS Week 1 to Week 12 Primary Schools

TOPIC – WEIGHT (GRAMS, KILOGRAMS AND TONNES)

LEARNING AREA

1. Relationships between Grams, Kilograms and Tonnes

2. Addition and Subtraction of Weight

3. Multiplication and Division of Weight

4. Word Problems Involving Weight

PERFORMANCE OBJECTIVES

By the end of the lesson, the pupils8 should have attained the following objectives (cognitive, affective and psychomotor) and should be able to –

1. To use standard units.

2. Express the same weight in different unit gram, kilogram, tonne.

3. Solve word problems on weights.

ENTRY BEHAVIOUR

INSTRUCTIONAL MATERIALS

The teacher will teach the lesson with the aid of:

1. Samples of different objects.

2. Weighing scales.

3. Spring balance.

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 ONE – INTRODUCTION TO CAPACITY

Pupil’s Activities 1 – Identify the objects on the chart and mention its uses.

1. Body weight scales

2. Kitchen scales

3. Spring scales

They are all used for measuring weights of an object, for example – body, food items, iron, aluminum, plastic, etc.

Pupil’s Activities 2 – Comparing two or more objects of different sizes to determine their weight

Objects that can be compared,

1. Stones

2. Bag of rice, cement, etc.

3. Food items like rice, beans, chicken, meats, etc. If available.

Teacher’s remark – Weight is  the amount of matter in a body or an object. Size doesn’t determine weight. Sometimes, objects of the same size might have different weight.

Teacher’s/Pupil’s Activities 3 – Teacher and Pupils Weights

Teacher’s weight –

Pupil 1 –

Pupil 2 –

Pupil 3, etc.

Discussion on why body of small sizes have more weight than that of big size.

Teacher’s remark – Size doesn’t determine the weight. Sometimes, objects of small sizes have more or the weight with large size. Use some pupils as examples.

Pupil’s Activities 4 – Take Home

Find out the weight of the following items –

1. bags of rice, bean, semo.

2. Cartoon of indomie and satchel of Indomie.

3. Tin milk

LESSON TWO – UNITS OF WEIGHT (GRAM, KILOGRAM AND TONNE)

Pupil’s Activities 1 – Results of their findings

1. Rice – 50 kg (full bag), 30 kg, 25 kg, 10 kg and 5 kg.

2. Bean – 50 kg and 25 kg.

3. Semo – 10 kg and 5 kg.

4. Satchel of Indomie – 70 g

5. Tin milk – 14 g

Teacher’s remark – The basic units of weight are gram, kilogram and tonne. Tonne is bigger or larger objects with big mass. Each of the unit can be expressed as the unit of one another.

Teacher’s/Pupil’s Activities 2 – Relationship between Gram, Kilogram and Tonne

Observe and describe the units on the chart.

Gram (g) Kilogram (kg) Tonne (t)

1 000 grams (g) = 1 kilogram (kg)

1 000 kilograms = 1 tonne (t)

1 tonne = 1 000 x 1 000 grams = 1 000 000 g

Teacher’s/Pupil’s Activities 3 – Conversion involving unit of weight

Study the following conversion

1 000 g = 1 kg

1 100 g = 1.1 kg

1 010 g = 1.01 kg

1 001 g =. 1.001 kg

2 000 g = 2 kg

2 500 g = 2.5 kg

Illustration

1 000 g = 1 kg

1 100 g = 1 000 g + 100 g = 1.1 kg

1 000 g + 10 g = 1.01 kg

1 001 g = 1 000 g + 1 g =. 1.001 kg

1 000 g + 1 000 g = 2 000 g = 2 kg

1 000 g + 1 000 g + 500 g = 2 500 g = 2.5 kg

Working Examples

1. 15 kg

1 000 g = 1 kg

= 1 000 g x 15

= 15 000 g

2. 12 132 g

1 000 g = 1 kg

12 132 g/1 000 g = 12.132 g

Teacher’s/Pupil’s Activities 2 – Class Exercise/Take

Change these to grams.

1. 23 kg

2. 105 kg

3. 29.2 kg

Change these to kilograms.

1. 17. 11 000 g

2. 18. 27 726 g

3. 19. 400 g

LESSON THREE – ADDITION AND SUBTRACTION INVOLVING WEIGHT

Pupil’s Activities 1 – Addition and Subtraction of Weight

Working Examples

1. 14 kg 620 g + 42 kg 123

2. 44 kg 452 g — 16 kg 115 g

Solutions

1. 14 kg 620 g + 42 kg 123 g

14 kg 620 g

42 kg 123 g (+)

___________

56 kg 743 g

2. 44 kg 452 g — 16 kg 115 g

44 kg 452 g

16 kg 115 g (—)

___________

38 kg 337 g

Pupil’s Activities 2 – Class Exercise/Take Home

Solve the following.

1. 5 kg 830 g + 16 kg 296 g

2. 71 kg 672 g + 25 kg 759 g

3. 94 kg 358 g – 30 kg 660 g

4. 48 kg 411 g – 33 kg 738 g

LESSON FOUR – MULTIPLICATION AND DIVISION INVOLVING WEIGHT

Teacher’s/Pupil’s 1 – Working Examples

1. 25 kg 254 g x 12

2. 64 kg 824 g ÷ 8

Solutions

25 kg 254 g x 12

25 kg 254 g

x           12

___________

50 kg 508 g

25 kg 254 g (+)

___________

75 kg 762 g

8 kg   14 g

____________

8√(64 kg 824 g)

(—) 64 kg 824 g

___________

00 kg 000 g

Pupil’s Activities 2 – Class Exercises/Take Home

1. 94 kg 358 g x 12

2. 30 kg 660 g x 5

3. 48 kg 424 g ÷ 2

4. 42 kg 366 g ÷ 6

LESSON FIVE – WORD PROBLEMS INVOLVING WEIGHT

Teacher’s/Pupil’s Activities – Working Examples and Class Exercises

1. A salesman sold 578 kg 450 g of rice in November and 763 kg 310 g of rice in December. How much rice did he sell in November and December?
2. Ayomide weighs 5.6 kg than Michael, who weighs 36.5 kg. What is Ayomide’s weight?
3. A bag of bean weighs 23 kg 300 g. The bag alone weighs 7 kg 550 g. What is the weight of the rice?
4. The lightest girl in Michelle’s class weighs 39.6 kg. The heaviest girl weighs 47.9 kg. What is the difference between the weights of the heaviest girl and the lightest girl in Michelle’s class?

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 obtain measures of their weight or other objects using weighing scales.

Pupil’s Activities – Knowing their weight.

3. Guides pupils to express the weights in different units.

Pupil’s Activities – Convert weights to different units.

4. Guides pupils to solve word problems on weight.

Pupil’s Activities – Solve word problems on weights.

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. convert weights expressed in tons to kilograms and vice versa.

2. solve word problem involving weights.