Metric to Metric Conversions
Objectives
Learn how to convert on metric unit to another
Since the metric system is based on the number 10, converting from one metric unit to another
is as easy as moving the decimal point. Moving the decimal does the same thing as multiplying or
dividing by a power of 10 (100, 1,000, 1 etc). Before the decimal can be moved, one needs to decide
which way to move it and how far. Learning the metric number line is critical to doing this- as in you
need to study it, learn it, remember it, memorize it, etc.! The metric number line is shown below:
Numerical value 1,000
100
10
1
.1
.01
.001
Prefix
kilohectodekabase
decicentimilliAbbreviation
k
h
da
m,L,g
d
c
m
Notice the “words” are prefixes and therefore will be added to the front of the base units- meter, liter
and gram. An easy way to remember the number line in order the by using the sentence- King Henry
Died Monday Drinking Chocolate Milk. The first letter of each word represents the first letter of each
prefix. Also notice the L for liter is capitalized.
With that part done, next you need to know which way to move the decimal. Here are the 2
rules:
1. When converting from a larger unit to a smaller unit, move the decimal to the right.
2. When converting from a smaller unit to a larger unit, move the decimal to the left.
Or even easier than that is to use the number line. Find the unit you are converting from. Next locate
the one you are converting to. Is the one you are converting to, to the left or right of the one you are
starting at? Move the decimal that way. Be aware that the terms larger and smaller are relative terms.
A centigram can be a large unit when compared to a milligram.
Next decide how far to move the decimal. Simple count the places over to the new unit from
the one you are converting from.
Finally find the decimal in the number you are converting, and move the decimal the same way
and the same number of places.
Here is how it all works. In a lab, you may need to convert a measurement like 25.89g to kg.
Grams (g) is smaller than kilograms (kg). So the decimal will need to go to the left. Grams is 3 places
away from kilograms, therefore the decimal will go three places to the left making 25.89g = .02589kg.
A common mistake is not to pay attention to sig. figs. The new number can have no more sig
figs than the original.
All measurements require a label. Leave the label off and a measurement is just a number.
Leave a label off and you will lose points! The label will consist of the abbreviations for the unit and its
prefix. For example, the label for milligram is mg. If there is no prefix, then just use the abbreviation for
the base unit.
Refer to the website shown below for further information and examples if needed.
http://www.visionlearning.com/library/module_viewer.php?mid=47
1. Write the rule used when converting from a small unit to a larger one.
2. Write the rule used when converting from a large unit to a smaller one.
3. What property of the metric system allows this to be done?
*How would you convert from one standard (English) measurement to another- say from tablespoons to
cups? ( The answer is not in the reading.)
4. In order to convert within the metric system easily, you need to know the metric prefixes in
order from largest to smallest. What is an easy way to remember it?
5. How is a label written if the measurement is taken in one of the base units?
6. How is the label written if the measurement is taken in a unit other than a base unit?