Millimeters, Centimeters, Meters and Kilometers
Basics on the topic Millimeters, Centimeters, Meters and Kilometers
Metric Units – Kilometers, Meters, Centimeters and Millimeters
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 centimeters, kilometers, and millimeters? They are all metric units of measurements for length! From smallest to largest measurement, we have millimeters, centimeters, meters, and kilometers!
Look at the above chart. What is between millimeters and kilometers? Centimeters and meters are between millimeters and kilometers!
Metric Units – Relationship
How do you relate meters (m), centimeters (cm), millimeters (mm) and kilometers (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 millimeters first. There is one million millimeters in a kilometer, one thousand millimeters in one meter, and one hundred millimeters in a centimeter.
Now let’s look at centimeters. There is one hundred thousand centimeters in a kilometer, and one hundred centimeters in a meter.
Now let’s look at meters. There is one thousand meters in a kilometer.
Metric Units – Examples
How Big are millimeters, centimeters, kilometers, and meters? Let’s look at examples from the real world for millimeters, centimeters, meters and kilometers.
A millimeter is roughly the size of the thickness of a paper clip.
A centimeter is roughly the length of a bug.
A meter is roughly the length of a guitar.
A kilometer is roughly the distance between the support towers on the Golden Gate Bridge.
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. 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 
As you can see, each metric unit of measurement is related to another metric unit of measurement. So with the help of this chart, you can decide for what kinds of distances you would choose to make measurements in millimeters, centimeters, meters and kilometers. After watching the video, you will find interactive exercises, worksheets and more activities for extra practice on metric units of measurement.
Transcript Millimeters, Centimeters, Meters and Kilometers
"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 millimeters, centimeters, Meters, and kilometers. Metric measurements, or units, of length that we use are kilometers, meters, centimeters, and millimeters. A millimeter is a small measure of length, and is represented by the abbreviation mm. A centimeter is a bigger measurement than millimeters, and is represented by the abbreviation cm. A meter is a bigger measurement than a centimeter, and is represented by the abbreviation m. A kilometer is a bigger measurement than a meter, and is represented by the abbreviation km. Let's take a closer look at millimeters! Ten millimeters make up one centimeter, one thousand millimeters make up one meter, and one million millimeters make up one kilometer. In fact the word milli in millimeter means million. You can use this to remember that a million millimeters make up one kilometer. Now let's take a look at centimeters! One hundred centimeters make up one meter, and one hundred thousand centimeters make up one kilometer. In fact, the word centi in centimeter is from the word century, which means one hundred. You can use this to remember that one hundred centimeters make up one meter. Now let's take a look at meters! One thousand meters make up one kilometer. And finally, let's look at kilometers! This is the biggest unit of length we are seeing here, and we can remember how many meters make up one kilometer by looking at the word kilo. Kilo means one thousand. You can use this to remember that a thousand meters make up one kilometer. What are some items or objects that are about the size of each unit? The thickness of a paperclip is roughly one millimeter. Some insects can be roughly one centimeter long. A guitar is roughly one meter. For one kilometer, there isn't a specific item that is one kilometer long, but the distance between the support towers on the Golden Gate Bridge is pretty close at just over one kilometer! While Zuri and Freddie finish up exploring the measuring kit, let's review! Remember, a millimeter is a small measure of length, and is represented by the abbreviation mm. A centimeter is a bigger measurement than millimeters, and is represented by the abbreviation cm. A meter is a bigger measurement than a centimeter, and is represented by the abbreviation mm. A kilometer is a bigger measurement than a meter, and is represented by the abbreviation km. "Order now to get my Weighted Wonders kit!" "No Zuri, Please don't." "I'll take one of the Weighted Wonders kits please!"
Millimeters, Centimeters, Meters and Kilometers exercise

Abbreviating units of measure.
HintsAbbreviations usually include the first letter of the word.
All the abbreviations will have the letter m which would represent "meters" because it is the metric system.
Am abbreviation is a shortened form of a word or phrase. For example United States of American can be represented as USA.
Solution millimeters: mm
 centimeters: cm
 meters: m
 kilometers: km

Ordering metric units.
HintsThe smallest unit of measurement goes at the top.
The largest unit of measurement goes at the bottom.
There are 1,000 meters in a kilometer.
SolutionMetric units of length from smallest to largest:
 millimeters (mm)
 centimeters (cm)
 meters (m)
 kilometers (km)

Estimate the length of the objects.
HintsSmaller objects need to be measured using a smaller unit of measurement.
Think of the size of the object to help decide what unit is best used to measure it.
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.
HintsReview the definition of each unit of measurement.
Use the metric unit conversion table to help complete the statements.
Use this comparison chart to help you complete the statements above.
Solution There are a million millimeters in one kilometer.
 The word centimeter stems from the word century meaning 100.
 One kilometer is equal to 1,000 meters.
 Kilometers are the largest metric unit for measuring length.
 The word kilo means 1,000.

Which units would measure each object?
HintsSmaller objects should be measured using smaller units of measurement.
Use this comparison chart to help you decide on the units used to measure each item.
SolutionThe items would be measured using the following units:
 the beetle: yellow (millimeters)
 the paperclip: yellow (centimeters)
 the guitar: blue (meters)
 the bridge: violet (kilometers)

Convert the metric units of measurement.
HintsUse these conversions to help:
 1,000 mm = 1 m
 100 cm = 1 m
 1 km = 1,000 m
If converting from a smaller unit to a larger unit (such as centimeters to meters), you divide.
If converting from a larger unit to a smaller unit (such as meters to centimeters), you multiply.
Solution 1 km = 1 mm is not correct ❌ because 1km is 1 million millimeters.
 1,000 m = 1 km is correct ✅.
 100 cm = 1m is correct ✅.
 10mm = 1m is not correct ❌ because 10 mm is = to 1 centimeter.
 2 km = 2,000 m is correct ✅.
 3 m = 300 cm is correct ✅.