CLASS: Basic 3
Weight describes how heavy or light an object is. We can compare objects by using their weight because, some objects are heavy while some objects are light.
- A bag of sugar weighs more than a loaf of bread.
An eraser weighs less than a cup.
Your mathematics text book weighs more than your exercise book.
We can measure or know the weight of an object by using weighing scales. Examples of different weighing scales are:
All of these are used to measure the weight of different objects.
STANDARD UNITS OF WEIGHT
(i) The kilogram (kg) is used as a unit when we weigh heavy objects like bag of rice, bag of cement, etc.
(ii) The gram (g) is used when we weigh lighter objects like pencils, rulers, etc.
Relationship Between Grams (g) and Kilograms (kg).
When we have 1000g = 1kg (that is 1000grams is the same as 1kilogram)
We can change grams to kilograms and change kilograms to grams.
Know that: When you want to change grams to kilograms you divide by 1000.
Example: change 2000g to kilogram
2000 ÷ 1000 = 2kg
Also know that: When you want change kilograms to grams you multiply by 1000.
Examples: (i) change 2kg to grams.
2 × 1000 = 2000g
(ii) Change 1/4kg to grams.
1/4 × 1000
1 × 1000/4
1000/4 = 250g
Answer these questions:
Compare these objects by using (more than or less than)
A bottle of water weighs ______________ An empty bottle.
A pineapple weighs ______________ an orange.
A hen weighs ____________ a dog.
An exercise book weighs ____________ your school bag.
Change 4000g to kilograms
Change 7kg to grams
Change 1/2 kg to grams
Change 2500g to kilograms.