SI prefixes
SI units may be combined with prefixes to denote multiplication by a power of 10.
 You need to know most of these prefixes, certainly those in bold in the table.
  e.g. 1 µm = 1×10–6 m, e.g. 5 MW = 5×106 W.
| 10-1 | deci | d | 101 | deca | da | |
| 10-2 | centi | c | 102 | hecto | h | |
| 10-3 | milli | m | 103 | kilo | k | |
| 10-6 | micro | µ | 106 | mega | M | |
| 10-9 | nano | n | 109 | giga | G | |
| 10-12 | pico | p | 1012 | tera | T | |
| 10-15 | femto | f | 1015 | peta | P | |
| 10-18 | atto | a | 1018 | exa | E | |
| 10-21 | zepto | z | 1021 | zetta | Z | |
| 10-24 | yocto | y | 1024 | yotta | Y |