Symbols for Volt and voltage The symbols for Volt and for voltage are both $V$. Usually, the meaning of $V$ is clear enough from context to avoid confusion. However, I find a bit odd when both $V$ appear in the same formula. For example:
$$V=I \cdot R={10A} \cdot {5 \Omega}=50V$$
Is there an international standard how to write that more clearly?
I'm looking for a way that could be easily used in LaTex or Mathjax, but other information about what the usual notation is will also be welcomed.
 A: The SI brochure, which defines the International System of Units and makes recommendations about its usage, specifies that (§5.4.1, emphasis mine)

Symbols for quantities are generally single letters set in an italic font

and that

Unit symbols are printed in upright type regardless of the type used in the surrounding text.

Therefore, your example should become
$$V =IR = 10\,\mathrm{A}\times 5\,\Omega= 50\,\mathrm{V}$$
Note also another change in the above, I've used a cross for the product of the two quantity values instead of the centred dot. In fact (§5.4.6),

When multiplying the value of quantities either a multiplication sign
× or brackets should be used, not a half-high (centred) dot. When
multiplying numbers only the multiplication sign × should be used.

You can find other information on how to write values in different contexts and a complete list of references about quantities, units and quantity calculus in this answer of mine on Academia SE. And if you use $\LaTeX$, there is the package siunitx which handles the formatting of quantities and units according to the SI brochure in an easy way.
Finally, note also that quantity names like volt, ampere etc. should start with a lower case initial (e.g. ampere is the unit, Ampère is the scientist).
