What Are The Basics Of The Metric System?

The metric system is named after its principal unit of length. That is the meter, derived from the Greek word me´tron, meaning a measure. As determined originally, the length of a meter is one ten millionth the distance between the North Pole and the earth's Equator, measured along the meridian from Barcelona, Spain, to Dunkirk, France. Perhaps you really want to get technical. Well, according to present internationally accepted standards, the meter is defined as 1,650,763.73 wavelengths of the orange-red light from krypton-86 (an isotope of the inert gaseous element krypton) as measured in a vacuum. But those using the Customary system will find it much easier to think of the unit of length that they call a yard, and then add three and a third inches. Whereas the yard is 36 inches long, the meter is 39.37 inches in length.
Today's metric system has six base units. For the unit of length, there is the meter. That of mass (commonly termed "weight") is the kilogram. In the case of temperature it is the kelvin (translated into degrees Celsius, formerly centigrade). The time unit is the second. For electric current we have the ampere. And the candela is the unit of luminous intensity. Of course, the system includes other units, such as that for speed, but all are derived from the base units just mentioned. Incidentally, the second, ampere and candela are used in the Customary system too.
One feature of the metric system is its simplicity. When you are 'thinking metric' ten is the basic number to remember, for you are using a decimal system. Start with a base unit. Then either divide or multiply by ten. To designate resulting quantities, just add standard prefixes.