## What you need to know

Things to remember:

• We do the opposite of what you think we might do.
• To get from bigger units to smaller units, we have to multiply.
• The numbers move to the left.
• To get from smaller units to bigger units, we have to divide.
• The numbers move to the right.

We have seen kilometres before, but let’s have a quick recap.

$$1km = 1000m$$

How do we turn 1 into 1000? We multiply by 1000! So, to turn km into m, we multiply by 1000.

$$\text{km to m} \rightarrow \times1000$$

But if we want to go back from m to km, we have to do the opposite… divide by 1000!

$$\text{m to km} \rightarrow \div1000$$

What is 3.25km in m?

$$\text{km to m} \rightarrow \times1000$$

Hint: To multiply by 1000, we move the numbers to the left three place values.

$$3.25\times1000=3250$$

3.25km = 3250m

What is 267m in km?

$$\text{m to km} \rightarrow \div1000$$

Hint: To divide by 1000, we move the numbers to the right three place values.

$$267\div1000=0.267$$

267m = 0.267km

If we’re looking at smaller units, like m and cm, we need to remember that:

1m = 100 cm

How do we turn 1 into 100? We multiply by 100! So, to turn m into cm, we multiply by 100.

$$\text{m to cm} \rightarrow \times100$$

But if we want to go back from cm to m, we have to do the opposite… divide by 100!

$$\text{cm to m} \rightarrow \div100$$

What is 2.77m in cm?

$$\text{m to cm} \rightarrow \times100$$

Hint: To multiply by 100, we move the numbers to the left two place values.

$$2.77\times100=277$$

2.77m = 277cm

What is 57cm in m?

$$\text{cm to m} \rightarrow \div100$$

Hint: To divide by 100, we move the numbers to the right left two place values.

$$57\div100=0.57$$

57cm = 0.57m

Converting between units of volume should be a lot easier now, if we remember that 1L = 1000ml. This is the same conversion as with km and m!

$$\text{L to ml} \rightarrow \times1000$$

But if we want to go back from ml to L, we have to do the opposite… divide by 1000!

$$\text{ml to L} \rightarrow \div1000$$

What is 5.896L in ml?

$$\text{L to ml} \rightarrow \times1000$$

Hint: To multiply by 1000, we move the numbers to the left three place values.

$$5.896\times1000=5896$$

5.896L = 5896ml

What is 753ml in L?

$$\text{ml to L} \rightarrow \div1000$$

Hint: To divide by 1000, we move the numbers to the right three place values.

$$753\div1000=0.753$$

753ml = 0.753L

Luckily for us, 1kg=1000g, so we can use the same conversions… AGAIN!

$$\text{kg to g} \rightarrow \times1000$$

But if we want to go back from g to kg, we have to do the opposite… divide by 1000!

$$\text{g to kg} \rightarrow \div1000$$

What is 3.201kg in g?

$$\text{kg to g} \rightarrow \times1000$$

Hint: To multiply by 1000, we move the numbers to the left three place values.

$$3.201\times1000=3201$$

3.201kg = 3201g

What is 15g in kg?

$$\text{g to kg} \rightarrow \div1000$$

Hint: To divide by 1000, we move the numbers to the right three place values. We will need to add some extra 0s!

$$15\div1000=0.015$$

15g = 0.15kg

## Example Questions

#### Question 1: What is 4.46km in m?

$$\text{km to m} \rightarrow \times1000$$

Hint: To multiply by 1000, we move the numbers to the left three place values.

$$4.46\times1000=4460$$

4.46km = 4460m

#### Question 2: What is 23ml in L?

$$\text{ml to L} \rightarrow \div1000$$

Hint: To divide by 1000, we move the numbers to the right three place values. We’ll need an extra 0 here!

$$23\div1000=0.023$$

23ml = 0.023L
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