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Year 6 Maths Measurement

Mass & Capacity

Learn to convert between units of mass and capacity, estimate measurements, and solve real-world problems using metric units.

Units of Mass

In Australia we use the metric system. Mass tells us how heavy something is. The main units are milligrams (mg), grams (g), kilograms (kg) and tonnes (t).

1 t = 1 000 kg    |    1 kg = 1 000 g    |    1 g = 1 000 mg

Everyday Examples

  • A paperclip ≈ 1 g
  • A loaf of bread ≈ 500 g
  • A bag of sugar ≈ 1 kg
  • A small car ≈ 1 t

Converting Mass

  • kg to g: multiply by 1 000
  • g to kg: divide by 1 000
  • t to kg: multiply by 1 000
  • g to mg: multiply by 1 000

Units of Capacity

Capacity measures how much liquid a container can hold. The main units are millilitres (mL), litres (L) and kilolitres (kL).

1 kL = 1 000 L    |    1 L = 1 000 mL

Everyday Examples

  • A teaspoon ≈ 5 mL
  • A can of soft drink ≈ 375 mL
  • A milk carton ≈ 1 L
  • A backyard pool ≈ 50 kL

Converting Capacity

  • L to mL: multiply by 1 000
  • mL to L: divide by 1 000
  • kL to L: multiply by 1 000

Converting Between Units

The key idea: going from a larger unit to a smaller unit, you multiply. Going from a smaller unit to a larger unit, you divide.

Example: Convert 3.5 kg to grams

Step 1: kg is larger than g, so multiply.

Step 2: 3.5 × 1 000 = 3 500 g

Example: Convert 4 250 mL to litres

Step 1: mL is smaller than L, so divide.

Step 2: 4 250 ÷ 1 000 = 4.25 L

Key Vocabulary

Mass

The amount of matter in an object, measured in grams or kilograms.

Capacity

The amount of liquid a container can hold, measured in litres or millilitres.

Convert

To change a measurement from one unit to another (e.g. kg to g).

Estimate

To make a reasonable guess of a measurement using known benchmarks.

Worked Examples

1

A recipe needs 750 g of flour and 1.2 kg of sugar. What is the total mass in kilograms?

Step 1: Convert 750 g to kg: 750 ÷ 1 000 = 0.75 kg.

Step 2: Add: 0.75 + 1.2 = 1.95 kg.

Answer: 1.95 kg

2

A fish tank holds 45 L. How many millilitres is that?

Step 1: L to mL: multiply by 1 000.

Answer: 45 × 1 000 = 45 000 mL

3

A truck carries 2.5 tonnes of gravel. How many kilograms is that?

Step 1: t to kg: multiply by 1 000.

Answer: 2.5 × 1 000 = 2 500 kg

Knowledge Check

Select the correct answer for each question.

Question 1

Convert 6.2 kg to grams.

Question 2

How many litres is 3 500 mL?

Question 3

Which is the best estimate for the mass of a Year 6 student?

Question 4

A bottle holds 1.5 L. How many 250 mL cups can be filled from it?

Question 5

A parcel weighs 2 400 g. Another weighs 1.8 kg. What is the total mass in kg?

Key Concepts Summary

Problem Solving