The International System of Units is called "SI"
and is the Metric Measurement used in America.
EVOLUTION OF ARCHAIC MEASUREMENT
   Many years ago there was very little trade and measurement was crude and subject to confusion. The yard was supposed to be half the span from finger-tip to finger-tip of a King’s outstretched arms. And the pound was the
"weight of 7,000 grains of barley chosen from the middle ear".
   Rough and inaccurate measurement was good enough for barter between friends and relatives but trouble arose when commercial trade began. Relationships evolving out of haphazard methods of measurement were
anything but simple.
   And as merchants adopted a form of measurement that would be met with more acceptance by the general public of that era the outcome resulted in having 2 pints to the quart,
4 quarts to the gallon, 22 yards to a chain,
16 ounces to the pound
(is that ounces of nuts or ounces in a can of juice?)
12 inches to a foot,
(a foot isn't anywhere close to a human foot)
3 feet in a yard, 5,280 feet in a mile,
firkens and knogenheads, and so on and on and on.
   A pound even had five varied weights and meanings used throughout the Middle Ages and in Britain weight was measured as 14 pounds to the "stone". An outdated and archaic method of measurement seemingly reserved for
British colonies in America's past.
   The irony in this is that after the British were defeated the American gallon remained the outdated measurement adopted from what was known as the "Queen Ann's Wine Gallon". 
And still remains today.
   Notwithstanding all of these things, an international system of measurement has evolved today in America that was assisted in it's development as a result of for-sighted American Fathers like Thomas Jefferson who gave us an American dollar with 100 cents and
Dr Benjamin Franklin who, along with other devoted attendees of the Academy of Sciences in Paris contributed significantly to the design and simplicity of measuring in metric dimensions for Americans today.

Regardless of political or religious persuasion, ethnic or educational background, race, age or sex we can all learn from this because decimal measurement works in harmony with life itself. And it is all simply related in our human dimensions... in 10!
Even for a Primate It Makes Sense!
METRIC LEARNING TIP

DID YOU KNOW? ( Video) that you can divide 1 meter by exactly 10 equal parts (10 cm x 10 cm x 10 cm)... then make a cube (1000 cm³) of it to fill with water... and you will find that it contains exactly 1 L (1 litre) (1000 mL) of water... and is the mass of exactly 1 kg (1 kilogram) (1000 g). ALL SIMPLY RELATED IN 10!