First you need the basics to understand the metric system.
The metric system is based on a decimal system (ie:powers of ten). Therefore, it simplifies calculations by using a set of prefixes shown in the table below.
Multiplication Factor
Prefix
Symbol
U.S Name
1,000,000,000 = 10 9
giga
G
billion
1,000,000 = 10 6
mega
M
million
1,000 = 10 3
kilo
k
thousand
100 = 10 2
hecto
h
hundred
10 = 10 1
deca
da
ten
1 = 1
one
0.1 - 10 -1
deci
d
tenth
0.01 = 10 -2
centi
c
hundredth
0.001 = 10 -3
mili
m
thousandth
0.000001 = 10 -6
micro
µ
millionth
0.000000001 = 10 -9
nano
n
billionth
Symbols must be written exactly as shown in the tables. Do not change the case, or add an "s" for the plural, or use abbreviations, or write a period after a symbol (unless it ends a sentence).
The symbols (not abbreviations) for SI units are the same all over the world, regardless of the local language spoken.