# Measuring In Centimetre and Metre Primary 3 Third Term Mathematics Lesson Notes Week 2

**Subject : Mathematics**

Topic : Measuring in Centimetre and Metre

Class : Primary 3

Term :Third Term

**Behavioural Objectives: At the end of the lesson, pupils should be able to:**

- Mention weight of objects in grams and kilograms
- Make meaningful comparison of weight of objects like rocks,minerals.

**CONTENT**

**COMPARING WEIGHT**

**A bottle of water weigh more than an empty bottle**

**A sister weighs less than a mug**

**A mathematics textbook weighs more than an exercise book.**

Activity

- Weigh the objects and record their weights in kilograms or grams.
- 6 packets of whiteboard markers 2. 3 tins of Milo
- 1 mathematics textbook 4. 1 bottle of water
- 10 packets of pencils 6. 1 tin of milk
- 1 bag of Semolina 8. 1 packet of biscuits
- 2 big tins of Peak Milk

### Standard units of weight

We need to use standard units to measure weight.

The kilogram (kg) is used as a unit when weighing heavy objects like

bags of rice, bags of cement, etc.

The gram (g) is used when weighing lighter objects like pencils, rulers, etc.

Measuring and estimating weight

These are different types of weighing scales

O

Exercise 2

Classify these objects according to their weight in grams and kilograms.

Name of objects Weight in grams (g) Weight in kilogram (kg)

- Bottle of water
- Pencil
- Eraser
- Bag of sugar
- Jug
- Ruler
- Stone
- Bottle of Fanta

Name of objects Weight in grams (g) Weight in kilogram (kg)

- Toothbrush
- Orange
- Rock
- Scissors
- 5 tins of Milo
- A bundle of nails
- 2 notebooks
- A baby boy

Grams and kilograms

1000 grams (g) = 1 kilogram (kg)

short form short form

We can convert weights in grams to kilograms and weights in kilograms to grams

Examples

2 kg = 1000 g + 1000 g = 2000 g

1/2kg = 1000 g ÷ 2 g = 500 g

2000 g = 2000 g ÷ 1000 g = 2 kg

Exercise 2

- Answer these.
- 1. How many kilograms are there in these:
- a) 3000 g = b) 2500 g = c) 4000 g =
- 2. What must I add to 700 g to make 1 kg?
- 3. How many grams are there in these:
- a) 1/2kg = b) 1/4kg = c) 3/4kg =
- 4. Which is greater?
- a) 2000 g or 11/2kg b) 1500 g or 1 kg c) 3500 g or 3 kg

- 1. Copy and complete the following. Use symbols > or <.
- a) 200 g[] 1/4kg b) 2/5kg[] 300 g c) 100 g[] 1/5kg d) 1 kg[] 700 g
- e) 900 g[] 3/4kg f) 400 g[] 1/2kg g) 3/5kg[] 1/2kg h) 3/4kg[] 1/2kg
- i) 800 g []3/4kg j) 2/5kg[] 1/4kg
- Copy and complete the following. Use the number line to help you.
- a) 1/2kg =[] g b) 3/4kg =[] g c) 1/5kg =[] g d) 1/4kg =[] g e) 2/5kg =[] g f) 1/10 kg =[] g g) 3/5kg =[] g h) 4/5kg =[] g
- Copy and complete the following. The first one is done for you.
- a) 11/2kg =[] 1 kg +[] 12kg

= 1 kg + 500 g

= 1 kg 500 g

- c) 31/4kg =[] kg +[] g

=[] kg +[] g

- e) 1/15kg =[] 1 kg +[] kg

=[] kg[] g

- b) 21/2kg =[] kg +[] 12kg=[] kg{} g

- d) 23/5kg ={}| kg +{} g

={} kg {}g

- f) 3 1/10 kg =() kg +() g

=() kg() g

Good morning, class! Today, we are going to learn about the weight of objects. We will be using two common units of measurement: grams and kilograms.

First, let’s talk about grams. Grams are used to measure the weight of smaller objects. For example, a paperclip or a pencil might weigh a few grams. So, we use grams to measure lightweight objects. We can write grams as “g.”

Now, let’s move on to kilograms. Kilograms are used to measure the weight of larger objects. For instance, a bag of rice or a watermelon would weigh several kilograms. So, we use kilograms to measure heavier objects. We can write kilograms as “kg.”

To give you a better understanding, let’s compare the weight of different objects. Imagine we have a small apple, a basketball, and a sack of potatoes. We would measure the weight of the small apple in grams, the basketball in kilograms, and the sack of potatoes in kilograms as well because it’s quite heavy.

To convert from grams to kilograms, we need to remember that there are 1,000 grams in 1 kilogram. So, if we have 1,500 grams, we can divide it by 1,000 to get 1.5 kilograms. Similarly, if we have 3,200 grams, we can divide it by 1,000 to get 3.2 kilograms.

Now, let’s practice a few examples together. Suppose we have a pencil that weighs 10 grams. Can anyone tell me how to write this weight in kilograms?

[Allow students to answer]

That’s right! To convert grams to kilograms, we divide by 1,000. So, 10 grams is equal to 0.01 kilograms because 10 divided by 1,000 is 0.01.

Let’s try another one. If we have a watermelon that weighs 5 kilograms, how many grams would it weigh?

[Allow students to answer]

Great job! To convert kilograms to grams, we multiply by 1,000. So, 5 kilograms is equal to 5,000 grams because 5 multiplied by 1,000 is 5,000.

Remember, when dealing with smaller objects, we use grams, and for larger objects, we use kilograms. Understanding the difference between grams and kilograms will help us accurately measure the weight of objects.

I hope that explanation helped you all understand the concept of measuring weight in grams and kilograms. If you have any questions, feel free to ask!

** **

Evaluation

1. A small paperclip would most likely be measured in __________.

a) grams

b) kilograms

c) liters

2. A bag of rice would most likely be measured in __________.

a) grams

b) kilograms

c) meters

3. 1 kilogram is equal to __________ grams.

a) 100

b) 1,000

c) 10,000

4. A watermelon weighing 3,500 grams can be written as __________ kilograms.

a) 3.5

b) 35

c) 350

5. An apple weighing 150 grams can be written as __________ kilograms.

a) 0.15

b) 1.5

c) 15

6. A large sack of potatoes would most likely be measured in __________.

a) grams

b) kilograms

c) centimeters

7. 2,500 grams is equal to __________ kilograms.

a) 0.25

b) 2.5

c) 25

8. A basketball weighing 800 grams can be written as __________ kilograms.

a) 0.08

b) 0.8

c) 8

9. A textbook weighing 2 kilograms can be written as __________ grams.

a) 200

b) 2,000

c) 20,000

10. 5 kilograms is equal to __________ grams.

a) 500

b) 5,000

c) 50,000

Take your time and fill in the blanks with the correct options. Good luck!

** **

Title: Weight of Objects in Grams and Kilograms

Grade: Primary 3

Subject: Mathematics

Duration: 45 minutes

I. Learning Objectives:

By the end of this lesson, students will be able to:

1. Differentiate between grams and kilograms as units of weight measurement.

2. Convert between grams and kilograms using appropriate conversion factors.

3. Apply the concepts of grams and kilograms to solve weight-related problems.

II. Embedded Core Skills:

1. Numeracy: Students will develop their numerical skills by performing conversions between grams and kilograms.

2. Measurement: Students will learn to measure and compare the weight of objects using appropriate units.

III. Learning Materials:

1. Whiteboard and markers

2. Chart or poster displaying the conversion factor between grams and kilograms

3. Examples of objects with their corresponding weights in grams and kilograms

4. Worksheets or activity sheets for practice

5. Weighing scale (optional)

IV. Presentation:

1. Begin the lesson by engaging the students in a short discussion about weight and the need for a standard unit of measurement.

2. Introduce the two units of weight measurement: grams and kilograms. Explain that grams are used for lighter objects, while kilograms are used for heavier objects.

3. Display the chart or poster with the conversion factor between grams and kilograms.

4. Provide examples of objects and ask students to estimate their weight in grams and kilograms.

5. Demonstrate how to convert between grams and kilograms using the conversion factor. Show step-by-step calculations and encourage students to follow along.

6. Use real-life examples to reinforce the concept. Show objects of different weights and ask students to identify whether they would measure them in grams or kilograms.

7. Facilitate a class discussion on the importance of using the correct unit of measurement when weighing objects.

V. Teacher’s Activities:

1. Explain the concept of weight in grams and kilograms.

2. Present examples and calculations to illustrate the conversion between grams and kilograms.

3. Facilitate class discussions and encourage student participation.

4. Provide clear explanations and guide students through the learning process.

5. Use visual aids and real-life examples to enhance understanding.

6. Monitor students’ progress and provide assistance as needed.

7. Provide feedback and reinforcement during activities and discussions.

VI. Learners’ Activities:

1. Actively listen and participate in class discussions.

2. Take notes during the presentation.

3. Practice converting weights between grams and kilograms.

4. Solve problems and complete worksheets or activity sheets.

5. Engage in group discussions and share their understanding with peers.

6. Ask questions when clarification is needed.

VII. Assessment:

1. Observe students’ participation and engagement during class discussions.

2. Monitor students’ progress during individual and group activities.

3. Review completed worksheets or activity sheets to assess understanding.

4. Provide verbal feedback and answer questions raised by students.

5. Assess students’ ability to convert weights between grams and kilograms accurately.

VIII. Ten Evaluation Questions:

1. What is the unit of measurement used for lighter objects?

2. What is the unit of measurement used for heavier objects?

3. How many grams are there in 1 kilogram?

4. Convert 3,500 grams to kilograms.

5. Convert 0.25 kilograms to grams.

6. Is a bag of apples likely to be measured in grams or kilograms?

7. Is a washing machine likely to be measured in grams or kilograms?

8. Convert 750 grams to kilograms.

9. Convert 4 kilograms to grams.

10. Explain why it is important to use the correct unit of measurement when weighing objects.

IX. Conclusion:

In conclusion, we have learned about the weight of objects in grams and kilograms. We now understand that grams are used for lighter objects, while kilograms