# Millimetres, Centimetres, Metres and Kilometres

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## Metric Units – Kilometres, Metres, Centimetres and Millimetres

What are kilometres, metres, centimetres and millimetres?

If you want to measure the length of something, you need to label length using units of measurement. There are different units in which we can indicate the length of something. What are centimetres, metres, kilometres, and millimetres? They are all metric units of measurements for length! From smallest to largest measurement, we have millimetres, centimetres, metres, and kilometres.

## Metric Measurement Relationship

How many metres are in a kilometre? How big is a metre in centimetres? These are questions you might find yourself asking. Millimetres, centimetres, metres and kilometre are all metric measurements of length! Let’s find out more about how they compare to each other. One unit on the left column equals the amount of the relatively smaller unit of measurement on the right.

Larger metric unit Smaller metric unit
1 centimeter 10 millimeters
1 meter 100 centimeters
1 kilometer 1,000 meters

Look at the above chart. Are kilometres bigger than metres? Yes, we can see that from the chart. We can also see that metres are bigger than centimetres and centimetres and bigger than millimetres.

How do you relate metres (m) to kilometres (km)? Each unit of measurement relates to the others, because you have so many of one, in a number of the other.

For example, let’s look at millimetres first. There is one million millimetres in a kilometre, one thousand millimetres in one metre, and one hundred millimetres in a centimetre.

Now let’s look at centimetres. There is one hundred thousand centimetres in a kilometre, and one hundred centimetres in a metre. Let’s look at examples from the real world for each metric unit of measurement.

Now let’s look at metres. There is one thousand metres in a kilometre.

## Metric Units – Examples

A millimetre is roughly the size of the thickness of a paper clip.

A centimetre is roughly the length of a bug like this one.

A metre is roughly the length of a guitar.

A kilometre is roughly the distance between the support towers on the Golden Gate Bridge in San Francisco, USA.

## Metric Units – Summary

The metric units for measuring length are millimeters, centimeters, meters, and kilometers. These units describe the length of objects from very small objects (measured in millimeters) to very large objects (measured in kilometers).

They are related because you can convert one to the other! Below is an overview of these four metric units of measurement.

They are related because you can convert one to the other! Below can find interactive exercises, worksheets and more activities concerning millimetres, centimetres, metres and kilometres.

## Frequently Asked Questions – Metric Units

What are kilometres, metres, centimetres and millimetres?
How many metres are in a kilometre?
Are kilometres bigger than metres?
How big is a metre in centimetres?

### TranscriptMillimetres, Centimetres, Metres and Kilometres

"If you call right now, you will get TWO measuring kits for the price of ONE, delivered immediately!" "I can't believe people fall for that, can you Zuri?"

"I'll take two measuring kits, please!"

"Well, you've purchased it now, might as well take a look." Let's join Zuri and Freddie as they learn all about Millimetres, Centimetres, Metres, and Kilometres. Metric measurements, or units, of length that we use are kilometres, metres, centimetres, and millimetres. A millimetre is a small measure of length and is represented by the abbreviation . A centimetre is a bigger measurement than a millimetre and is represented by the abbreviation . A metre is a bigger measurement than a centimetre and is represented by the abbreviation . A kilometre is a bigger measurement than a metre and is represented by the abbreviation . Let's take a closer look at millimetres! Ten millimetres make up one centimetre, one thousand millimetres make up one metre, and one MILLION millimetres make up one kilometre. In fact, the word MILLI in millimetre means MILLION. You can use this to remember that a MILLION millimetres make up ONE kilometre. Now let's take a look at centimetres! One hundred centimetres make up one metre, and one hundred thousand centimetres make up one kilometre. In fact, the word CENTI in centimetre is from the word CENTURY, which means ONE HUNDRED. You can use this to remember that one HUNDRED centimetres make up ONE metre. Now let's take a look at metres! One thousand metres make up one kilometre. And finally, let's look at kilometres! This is the biggest unit of length we are seeing here, and we can remember how many metres make up one kilometre by looking at the word KILO. KILO means one THOUSAND. You can use this to remember that a THOUSAND metres make up ONE kilometre. What are some items or objects that are about the size of each unit? The thickness of a paperclip is roughly one millimetre. Some insects can be roughly one centimetre long. A guitar is roughly one metre. For one kilometre, there isn't a specific item that is one kilometre long, but the distance between the support towers on the Golden Gate Bridge in San Francisco in the USA is pretty close at just over one kilometre! While Zuri and Freddie finish exploring the measuring kit, let's review! Remember, a millimetre is a small measure of length and is represented by the abbreviation . A centimetre is a bigger measurement than a millimetre and is represented by the abbreviation . A metre is a bigger measurement than a centimetre and is represented by the abbreviation . A kilometre is a bigger measurement than a metre and is represented by the abbreviation .

"Order now to get my Weighted Wonders kit!" "No Zuri, please don't..." "I'll take one of the Weighted Wonders kits please!"

## Millimetres, Centimetres, Metres and Kilometres exercise

Would you like to apply the knowledge you’ve learnt? You can review and practice it with the tasks for the video Millimetres, Centimetres, Metres and Kilometres.
• ### Abbreviating units of measure.

Hints

Abbreviations usually include the first letter of the word.

All the abbreviations will have the letter m, which would represent "metres" because it is the metric system.

Am abbreviation is a shortened form of a word or phrase. For example, United Kingdom can be abbreviated to UK.

Solution
• millimetres: mm
• centimetres: cm
• metres: m
• kilometres: km
• ### Ordering metric units.

Hints

The smallest unit of measurement goes at the top.

The largest unit of measurement goes at the bottom.

There are 1,000 metres in a kilometre.

Solution

Metric units of length from smallest to largest:

• millimetres (mm)
• centimetres (cm)
• metres (m)
• kilometres (km)

• ### Estimate the length of the objects.

Hints

Smaller objects need to be measured using a smaller unit of measurement.

This image is showing the distance between between places on a map.

Think about which object is the smallest. This would be measured in millimetres.

Use this comparison chart to help you decide on the units used to measure each item.

Solution
• The pencil end is about 5 mm.
• The crayon is about 5 cm.
• The fence is about 5 m.
• The distance from the two locations on the map is about 5 km.
• ### Complete the sentences about metric units.

Hints

People describe a century as 100 years. Does this help answer the question about cent?

Which metric unit has a part that sounds similar to million? Centimetre, millimetre or kilometre?

Solution
• There are a million millimetres in one kilometre.
• The word centimetre stems from the word century meaning 100.
• One kilometre is equal to 1,000 metres.
• Kilometres are the largest metric unit for measuring length.
• The word kilo means 1,000.
• ### Which units would measure each object?

Hints

The smallest item is the beetle and the largest item is the bridge.

Use this comparison chart to help you decide on the units used to measure each item.

You should use all four colours in the task. Each item should have a different colour assigned.

Solution

The items would be measured using the following units:

• the beetle: yellow (millimetres)
• the paperclip: green (centimetres)
• the guitar: blue (metres)
• the bridge: violet (kilometres)

• ### Convert the metric units of measurement.

Hints

Use these conversions to help:

• 1,000 mm = 1 m
• 100 cm = 1 m
• 1,000 m = 1 km

We know there are 100 cm in 1 metre. When we look at 300 cm, we have multiplied 100 by 3, so we also mulitply 1 m by 3 to find the equivalent in metres.

There are 10 mm in 1 cm. We multiply 1 cm by 100 to get a metre, so to find the equivalent in mm, we multiply 10 by 100.

Solution
• 1 km = 1 mm is not correct ❌ because 1 km is 1 million millimeters.
• 1,000 m = 1 km is correct ✅.
• 100 cm = 1 m is correct ✅.
• 10 mm = 1 m is not correct ❌ because 10 mm is equal to 1 centimetre.
• 2 km = 2,000 m is correct ✅.
• 3 m = 300 cm is correct ✅.