Metric units are easy to work with since they are all multiples of ten just like our place value chart. You can convert between the various sizes by shifitng back and forth with your place values or simply moving the decimal point the correct number of places.
The basic metric units are as follows:
meters (for length or distance)
grams (for mass or weight)
liters (for capacity or liquid volume)
There are many metric-unit prefixes, but the usual ones required in school are these: kilo-, hecto-, deka-, deci-, centi-, and milli-. To convert between the various sized units, we move up and down the place value chart.
You can use the following sentences to help remember the place vaules or prefixes:
King Henry Doesn't [Usually] Drink Chocolate Milk
King Henry Died [Unexpectedly] Drink Chocolate Milk
King Henry Does [Usually] Drink Chocolate Milk
The first letter stands for the prefixes, with "Usually" in the middle standing for the "unit" measures, which are meters, grams, or liters.
kilo- hecto- deka- [unit] deci- centi- milli-
Since each step is ten times larger or one-tenth smaller as the step on either side, we have:
1 kilometer = 10 hectometers = 100 dekameters = 1,000 meters
= 10, 000 decimeters = 100, 000 centimeters = 1, 000, 000 millimeters
Alternatively, we have:
1 milliliter = 0.1 centiliters = 0.01 deciliters = 0.001 liters = 0.000 1 dekaliters
= 0.000 01 hectoliters = 0.000 001 kiloliters
We move from one prefix (place value) to another by moving the decimal point either left or right as needed and filling in zeroes when necessary. Together with the prefix sentence ("King Henry..."), this makes conversion between the different metric sizes very simple.
How many jumps is it from "kilo-" to "centi-"? Five, to the right.
So I move the decimal point five places to the right, filling in the extra space with zeroes:
You don't have to make a loopy arrow like I did, but the loops help you keep track of the steps that you're counting, and make it really easy to see where to add the zeroes. After moving the decimal point and adding the zeroes, the answer would be:
- Convert 12.54 kilometers to centimeters.
12.54 km = 1 254 000 cm