Unit prefixes

### 8.1.7 Unit prefixes

You can insert a unit prefix in front of a unit to indicate a power of ten.
The following table gives the available prefixes:

Prefix | Name | (*10`^`) n | Prefix | Name | (*10`^`) n
Y | yota | 24 | d | deci | -1
Z | zeta | 21 | c | cent | -2
E | exa | 18 | m | mili | -3
P | peta | 15 | mu | micro | -6
T | tera | 12 | n | nano | -9
G | giga | 9 | p | pico | -12
M | mega | 6 | f | femto | -15
k or K | kilo | 3 | a | atto | -18
h or H | hecto | 2 | z | zepto | -21
D | deca | 1 | y | yocto | -24

Remark
You cannot use a prefix with a built-in unit if the result gives another built-in unit.
For example, 1_a is one are, but 1_Pa is one pascal and not 10`^`15_a.