In order to keep figures short and presentable, SI prefixes are often attached to units such as m (meter) or g (gram).
For example, a substance weighing 0.000 000 001 g may be described more simply as 1 ng (nanogram) or as 1000 pg (picograms).
Common prefixes of the International System of Units (SI) are:
p pico = 1 000 000 000 000th = 10-12
n nano = 1 000 000 000th = 10-9
µ micro = 1 000 000th = 10-6
m milli = 1 000th = 10-3
no prefix = 1
k kilo = 1 000 = 103
M Mega = 1 000 000 = 106
G Giga = 1 000 000 000 = 109
T Tera = 1 000 000 000 000 = 1012
