SI prefixes instead of decimal point In terms of readability and correctness, is replacing the decimal point with an SI prefix considered as good practice? When to use it and when not to? For example the value:
2700 Ω

can be written as:
2k7 Ω

Does any standard define this notation? I saw this notation a lot when I went to electrical engineering school.
 A: It's a practice in electrical engineering and it's mostly used for compactness. It's often used where space is limited as on schematics and components. Sometimes you even skip the $\Omega$ sign (since it can be inferred otherwise that it's a resistance).
Otherwise there's not much reason to use that notation otherwise because if space is not an issue, but not using it will make the notation understood in a wider circle.
A: This is of course a personal view. In a large number of years of academic scientific and mathematical research I have never seen it. I would never write a paper containing it. I would probably not recommend any paper containing it for publication without a change in its notation. Based on that anecdotal evidence, no, it is neither good nor standard in science or mathematics. It may be different in engineering disciplines.
I have doubts about it's clarity.
Consider expressing uncertainty:
$$
(4k7  \pm 1k4 )\,\Omega
$$
versus
$$(4.7  \pm 1.4 )\,k\Omega$$
To me the latter is much clearer.
Consider comparisons:
$$
\begin{cases}
1M0\,m\\
1k0\,m\\
1m0\,m
\end{cases}
$$
versus
$$
\begin{cases}
1.0 \times 10^6\,m\\
1.0 \times 10^3\,m\\
1.0 \times 10^{-3}m
\end{cases}
$$
To me the latter is much clearer.
