Step-by-step Maths Level 3: Choosing metres, centimetres, kilograms and grams
Part of the Step-by-step Maths Level 3 length and mass chapter. Chapter overview · whole chapter on one page
Choosing metres, centimetres, kilograms and grams
Length is how long something is. Use metres (m) for big things, and centimetres (cm) for small things.
Mass is how heavy something is. Use kilograms (kg) for heavy things, and grams (g) for light things.
Key ideas
- m and cm measure length.
- kg and g measure mass.
- Small things use cm and g. Big or heavy things use m and kg.
Method. Choose the unit that fits the size of the object.
- Think about how big or heavy it is. A pencil is about the size of a thing we can check easily.a pencil
- Choose the unit that fits. Big things are measured in metres. Small things are measured in centimetres.cm
- Write the answer. This is the unit to use.cm
Check. Think of a thing that is about the same size, so you can picture the unit.
Watch out. Metres and kilograms are large. Centimetres and grams are small.
Method. Choose the unit that fits the size of the object.
- Think about how big or heavy it is. A bag of sugar is about the size of a thing we can check easily.a bag of sugar
- Choose the unit that fits. Heavy things are weighed in kilograms. Light things are weighed in grams.kg
- Write the answer. This is the unit to use.kg
Check. Think of a thing that is about the same size, so you can picture the unit.
Watch out. Metres and kilograms are large. Centimetres and grams are small.
Method. Choose the unit that fits the size of the object.
- Think about how big or heavy it is. A door is about the size of a thing we can check easily.a door
- Choose the unit that fits. Big things are measured in metres. Small things are measured in centimetres.m
- Write the answer. This is the unit to use.m
Check. Think of a thing that is about the same size, so you can picture the unit.
Watch out. Metres and kilograms are large. Centimetres and grams are small.
Watch out
Watch out. A door is measured in metres, not centimetres. A paper clip is weighed in grams, not kilograms.
Exam tip
Grown-up tip. Ask: “Would you carry it, or would you need a trolley?” to help choose kg or g.
Exercise 9A Practice: choosing units
Non-calculatorMethod. Choose the unit that fits the size of the object.
- Think about how big or heavy it is. A bedroom wall is about the size of a thing we can check easily.a bedroom wall
- Choose the unit that fits. Big things are measured in metres. Small things are measured in centimetres.m
- Write the answer. This is the unit to use.m
Check. Think of a thing that is about the same size, so you can picture the unit.
Watch out. Metres and kilograms are large. Centimetres and grams are small.
Method. Choose the unit that fits the size of the object.
- Think about how big or heavy it is. A garden fence is about the size of a thing we can check easily.a garden fence
- Choose the unit that fits. Big things are measured in metres. Small things are measured in centimetres.m
- Write the answer. This is the unit to use.m
Check. Think of a thing that is about the same size, so you can picture the unit.
Watch out. Metres and kilograms are large. Centimetres and grams are small.
Method. Choose the unit that fits the size of the object.
- Think about how big or heavy it is. A bus is about the size of a thing we can check easily.a bus
- Choose the unit that fits. Big things are measured in metres. Small things are measured in centimetres.m
- Write the answer. This is the unit to use.m
Check. Think of a thing that is about the same size, so you can picture the unit.
Watch out. Metres and kilograms are large. Centimetres and grams are small.
Method. Choose the unit that fits the size of the object.
- Think about how big or heavy it is. A football pitch is about the size of a thing we can check easily.a football pitch
- Choose the unit that fits. Big things are measured in metres. Small things are measured in centimetres.m
- Write the answer. This is the unit to use.m
Check. Think of a thing that is about the same size, so you can picture the unit.
Watch out. Metres and kilograms are large. Centimetres and grams are small.
Method. Choose the unit that fits the size of the object.
- Think about how big or heavy it is. A rubber is about the size of a thing we can check easily.a rubber
- Choose the unit that fits. Big things are measured in metres. Small things are measured in centimetres.cm
- Write the answer. This is the unit to use.cm
Check. Think of a thing that is about the same size, so you can picture the unit.
Watch out. Metres and kilograms are large. Centimetres and grams are small.
Method. Choose the unit that fits the size of the object.
- Think about how big or heavy it is. A paper clip is about the size of a thing we can check easily.a paper clip
- Choose the unit that fits. Heavy things are weighed in kilograms. Light things are weighed in grams.g
- Write the answer. This is the unit to use.g
Check. Think of a thing that is about the same size, so you can picture the unit.
Watch out. Metres and kilograms are large. Centimetres and grams are small.
Method. Choose the unit that fits the size of the object.
- Think about how big or heavy it is. A strawberry is about the size of a thing we can check easily.a strawberry
- Choose the unit that fits. Heavy things are weighed in kilograms. Light things are weighed in grams.g
- Write the answer. This is the unit to use.g
Check. Think of a thing that is about the same size, so you can picture the unit.
Watch out. Metres and kilograms are large. Centimetres and grams are small.
Method. Choose the unit that fits the size of the object.
- Think about how big or heavy it is. A bicycle is about the size of a thing we can check easily.a bicycle
- Choose the unit that fits. Heavy things are weighed in kilograms. Light things are weighed in grams.kg
- Write the answer. This is the unit to use.kg
Check. Think of a thing that is about the same size, so you can picture the unit.
Watch out. Metres and kilograms are large. Centimetres and grams are small.
Method. Choose the unit that fits the size of the object.
- Think about how big or heavy it is. A book is about the size of a thing we can check easily.a book
- Choose the unit that fits. Big things are measured in metres. Small things are measured in centimetres.cm
- Write the answer. This is the unit to use.cm
Check. Think of a thing that is about the same size, so you can picture the unit.
Watch out. Metres and kilograms are large. Centimetres and grams are small.
Method. Choose the unit that fits the size of the object.
- Think about how big or heavy it is. A bag of apples is about the size of a thing we can check easily.a bag of apples
- Choose the unit that fits. Heavy things are weighed in kilograms. Light things are weighed in grams.kg
- Write the answer. This is the unit to use.kg
Check. Think of a thing that is about the same size, so you can picture the unit.
Watch out. Metres and kilograms are large. Centimetres and grams are small.
Method. Choose the unit that fits the size of the object.
- Think about how big or heavy it is. A sheet of paper is about the size of a thing we can check easily.a sheet of paper
- Choose the unit that fits. Heavy things are weighed in kilograms. Light things are weighed in grams.g
- Write the answer. This is the unit to use.g
Check. Think of a thing that is about the same size, so you can picture the unit.
Watch out. Metres and kilograms are large. Centimetres and grams are small.
Method. Choose the unit that fits the size of the object.
- Think about how big or heavy it is. A pencil is about the size of a thing we can check easily.a pencil
- Choose the unit that fits. Big things are measured in metres. Small things are measured in centimetres.cm
- Write the answer. This is the unit to use.cm
Check. Think of a thing that is about the same size, so you can picture the unit.
Watch out. Metres and kilograms are large. Centimetres and grams are small.
Method. Choose the unit that fits the size of the object.
- Think about how big or heavy it is. A bag of potatoes is about the size of a thing we can check easily.a bag of potatoes
- Choose the unit that fits. Heavy things are weighed in kilograms. Light things are weighed in grams.kg
- Write the answer. This is the unit to use.kg
Check. Think of a thing that is about the same size, so you can picture the unit.
Watch out. Metres and kilograms are large. Centimetres and grams are small.
Method. Choose the unit that fits the size of the object.
- Think about how big or heavy it is. A door is about the size of a thing we can check easily.a door
- Choose the unit that fits. Big things are measured in metres. Small things are measured in centimetres.m
- Write the answer. This is the unit to use.m
Check. Think of a thing that is about the same size, so you can picture the unit.
Watch out. Metres and kilograms are large. Centimetres and grams are small.
Method. Choose the unit that fits the size of the object.
- Think about how big or heavy it is. A bag of sugar is about the size of a thing we can check easily.a bag of sugar
- Choose the unit that fits. Heavy things are weighed in kilograms. Light things are weighed in grams.kg
- Write the answer. This is the unit to use.kg
Check. Think of a thing that is about the same size, so you can picture the unit.
Watch out. Metres and kilograms are large. Centimetres and grams are small.
Method. Choose the unit that fits the size of the object.
- Think about how big or heavy it is. A teaspoon of sugar is about the size of a thing we can check easily.a teaspoon of sugar
- Choose the unit that fits. Heavy things are weighed in kilograms. Light things are weighed in grams.g
- Write the answer. This is the unit to use.g
Check. Think of a thing that is about the same size, so you can picture the unit.
Watch out. Metres and kilograms are large. Centimetres and grams are small.