The Metric System is a decimal system with each component a multiple or subdivision of 10.
This means that conversions between metric units are much easier than English system conversions.
For example :
English System: 1 mile = 1,760 yards = 63,360 inches
Metric System: 1 kilometer = 1,000 meters = 100,000 centimeters
As you can see above, metric conversions only require a movement of the decimal.
The metric system is an international system of measurement. Only three countries have not made the official switch to the metric system and continue to use the customary system of measurement. This includes the United States! There are many advantages to switching, but other various factors must be taken into account. For example, the cost to switch could be extremely expensive when considering road signs alone. However, there are many other factors (both advantages & disadvantages) that you must consider as well - which you should research on your own.
Thankfully, in science, the metric system is used universally!
This is why we will use metric units in our chemistry class.
Assignment: Should the U.S. go metric?
Here is a link to compare viewpoints between both supporters and opponents of switching to the metric system: