In these lessons, we will look into two methods that can be used for metric conversion problems. The first method uses the metric table and can also be regarded as a shortcut method. The second method uses the unit fraction method.
Related Topics:
Introduction to the Metric System,
Metric Worksheets
Measurement Games
The metric system uses prefixes to denote multiple of 10.
The following table shows some common prefixes.
Prefix 
kilo 
hecto 
deka 
unit 
deci 
centi 
milli 
Symbol 
k 
h 
da 
d 
c 
m 

1,000 
100 
10 
1 
0.1 
0.01 
0.001 
Each prefix differs by a multiple of 10 from the next prefix. When converting between the different units of measure, we look at the number of “jumps” between the prefixes of the two units and then multiply or divide by the powers of 10 accordingly (moving to the right would mean to multiply and moving to the left would mean to divide).
Example :
Convert 3 km to m
Solution:
There are 3 “jumps” to the right from kilometer to meter.
So, we multiply by 10 ^{3} = 1000
3 km = 3 × 1,000 = 3,000 m
Example:
Convert 20 mm to cm
Solution:
There is 1 “jump” to the left from millimeter to centimeter
So, we divide by 10.
20 mm = 20 ÷ 10 = 2 cm
In this method, we multiply by a unit fraction in order to perform the metric conversion.
Example :
Convert 3 km to m
Solution:
Example:
Convert 20 mm to cm
Solution:
The following video shows more examples of metric conversion using the unit fraction method.