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Metric units of length review (mm, cm, m, & km)

Review the size of millimeters, centimeters, meters, and kilometers and how to convert between them.  Then, try some practice problems.

Summary of metric units of distance

KilometerMeterCentimeterMillimeter
11000100,0001,000,000
1100011001000
1100,0001100110

What is distance?

Distance measures length. For example, the distance of a road is how long the road is.
In the metric system of measurement, the most common units of distance are millimeters, centimeters, meters, and kilometers.

How big are metric units of distance?

A paper clip is about 1 millimeter thick.
A fingernail is about 1 centimeter wide.
The length of a guitar is about 1 meter.
A kilometer is equal to 1000 meters. It is a little over half of a mile.
Want to learn more about metric units of distance? Check out this video.

Practice set 1: Estimating distance

Problem 1A
Identify the most reasonable unit to measure the distance from New York to California.
Choose 1 answer:

Want to try more problems like this? Check out this exercise.

Converting larger units to smaller units

1 centimeter=10 millimeters
1 meter=100 centimeters
1 meter=1,000 millimeters
1 kilometer=1,000 meters
To convert larger units to smaller units we multiply the number of larger units by the green conversion factor for the appropriate smaller units.
Example: Converting meters to centimeters:
1 meter=100 centimeters
11 meters=11×100=1100 centimeters

Converting smaller units to larger units

1 millimeter=110 centimeter
1 centimeter=1100 meter
1 meter=11,000 kilometer
To convert smaller units to larger units we divide the number of smaller units by the purple conversion factor for the appropriate larger units.
Example: Converting meters to kilometers:
1 meter=11000 kilometer
7 m=71000=7÷1000=0.007 km
Want to learn more about converting between metric units of distance? Check out this video.

Practice set 2: Converting distance units

Practice 2A
Convert.
5 meters =
  • Your answer should be
  • an integer, like 6
  • an exact decimal, like 0.75
  • a simplified proper fraction, like 3/5
  • a simplified improper fraction, like 7/4
  • a mixed number, like 1 3/4
millimeters

Want to try more problems like this? Check out these exercises:
Convert larger units to smaller units
Converting between units

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