**WEEK 2&3**

**Subject: Mathematics**

**Class: Primary 3**

**Term: 3 ^{rd} Term**

**Topic: Weight**

**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

�

**Exercise 1**

**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**

**A. 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

**2. 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

**3. 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

b) 31/4kg =[] kg +[] g

=[] kg +[] g

c) 1/15kg =[] 1 kg +[] kg

=[] kg[] g

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

e) 23/5kg ={}| kg +{} g

={} kg {}g

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

=() kg() g

�

� Lesson Notes All Rights Reserved 2023