**Convert Between Larger and Smaller Units** *KS2 Revision*

## 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