7. Electrical Power: symbol (W). Read as Watt. It is capital W. Writing 100 W and 100 Watt is correct. 50 w or 50 Wt. or 50 Watts is not correct.
8. Volume: symbol (L). Read as Litre. It is capital L. Writing 10 L and 10 Litre is correct. 10 l or 10 lt. or 10 Litres or 10 ltr or 10 10 lit are incorrect forms.
Note: there are other base and derived units which need clarifications about their symbols and these will be shared shortly in some other article.
How to write numbers in the SI system of units? The followings are the rules and examples are provided for registering the numbers for science, engineering, technology-related measurements. This set of rules does not apply to financial data.