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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
start color #e07d10, 1, end color #e07d101000100, comma, 0001, comma, 000, comma, 000
start fraction, 1, divided by, 1000, end fractionstart color #e07d10, 1, end color #e07d101001000
start fraction, 1, divided by, 100, comma, 000, end fractionstart fraction, 1, divided by, 100, end fractionstart color #e07d10, 1, end color #e07d1010

## 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.

## Practice set 1: Estimating distance

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

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

## Converting larger units to smaller units

1, start text, space, c, e, n, t, i, m, e, t, e, r, end text, equals, start color #1fab54, 10, end color #1fab54, start text, space, m, i, l, l, i, m, e, t, e, r, s, end text
1, start text, space, m, e, t, e, r, end text, equals, start color #1fab54, 100, end color #1fab54, start text, space, c, e, n, t, i, m, e, t, e, r, s, end text
1, start text, space, m, e, t, e, r, end text, equals, start color #1fab54, 1, comma, 000, end color #1fab54, start text, space, m, i, l, l, i, m, e, t, e, r, s, end text
1, start text, space, k, i, l, o, m, e, t, e, r, end text, equals, start color #1fab54, 1, comma, 000, end color #1fab54, start text, space, m, e, t, e, r, s, end text
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, start text, space, m, e, t, e, r, end text, equals, start color #1fab54, 100, end color #1fab54, start text, space, c, e, n, t, i, m, e, t, e, r, s, end text
start color #11accd, 11, end color #11accd, start text, space, m, e, t, e, r, s, end text, equals, start color #11accd, 11, end color #11accd, times, start color #1fab54, 100, end color #1fab54, equals, start color #11accd, 11, end color #11accd, start color #1fab54, 00, end color #1fab54, start text, space, c, e, n, t, i, m, e, t, e, r, s, end text

## Converting smaller units to larger units

1, start text, space, m, i, l, l, i, m, e, t, e, r, end text, equals, start fraction, 1, divided by, start color #7854ab, 10, end color #7854ab, end fraction, start text, space, c, e, n, t, i, m, e, t, e, r, end text
1, start text, space, c, e, n, t, i, m, e, t, e, r, end text, equals, start fraction, 1, divided by, start color #7854ab, 100, end color #7854ab, end fraction, start text, space, m, e, t, e, r, end text
1, start text, space, m, e, t, e, r, end text, equals, start fraction, 1, divided by, start color #7854ab, 1, comma, 000, end color #7854ab, end fraction, start text, space, k, i, l, o, m, e, t, e, r, end text
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, start text, space, m, e, t, e, r, end text, equals, start fraction, 1, divided by, start color #7854ab, 1000, end color #7854ab, end fraction, start text, space, k, i, l, o, m, e, t, e, r, end text
start color #ca337c, 7, end color #ca337c, start text, space, m, end text, equals, start fraction, start color #ca337c, 7, end color #ca337c, divided by, start color #7854ab, 1000, end color #7854ab, end fraction, equals, start color #ca337c, 7, end color #ca337c, divided by, start color #7854ab, 1000, end color #7854ab, equals, start color #11accd, 0, point, 007, end color #11accd, start text, space, k, m, end text

## Practice set 2: Converting distance units

Practice 2A
Convert.
5 meters equals
millimeters

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

## Want to join the conversation?

• #1, I love the name, #2, A micrometer is 1000 times smaller than a centimeter.
• I have one tree that is 4 meters tall a second tree that is 3 m tall how many centimeters taller is the first tree
• 100 cm is the answer
• I get messed up with km to mm.
• Converting from km to m requires multiplying by 1,000, because there are 1,000 m in one km.

Converting m to mm requires multiplying by 1,000, because there are 1,000 mm in one m.

It follows from these two facts that converting from km to mm requires multiplying by 1,000*1,000=1,000,000.

Have a blessed, wonderful day!
• How many millimeters are in 5 meters?
• 5000 millimeters
• Does anyone know how long 1 meter = ----- kilometer and how long 1 kilometer = -----meter
• The prefix 'kilo' means 1000, so there are 1000 meters for every kilometer and there are 0.001 kilometers for every meter.
• Is there more measurements than just this?
• Yes- nanometers and micrometers are some smaller measurements
• How many kilometers in a mile?
• `if (x < 0) {thanks