You want to display the result of a calculation line in your dashboard ? You have one line with a lot of specific filters, and you want it linked directly to the dashboard, so you don't have to modify it in two different places ?
The report row widget is made for that !
For dashboard
How to find your line number ?
For Report (Daily report Only)
You will find the option to display report row value for yesterday. That will allow you more flexibility in your calculations.
Careful : The original report row cannot come from the same report as the widget Report row with the option display yesterday's values.