The use of certain other units is acknowledged but discouraged, and all other units should be avoided or used with caution.
Units have full names and abbreviations or symbols.
To these names or symbols prefixes may be used to indicate decimal multiples or sub-multiples of the unit. These prefixes are given in Table 1 . Compound prefixes, formed by juxtaposition of two or more prefixes, should not be used. When a prefix symbol is used with a unit symbol, the result is a single symbol, which may be raised to powers as a group.