This is probably on a roadmap somewhere, but in case it's not and I'm brilliant:
Currently, calculation columns allow us to apply equations across a row of a list report (e.g., if Feature A's due date is before today(), display text "Behind schedule.").
But we can't perform calculation on data in columns of that list report, as you typically could in a spreadsheet.
Use cases:
Will you be adding this capability? It would be super helpful.
Ditto for summing up scores
Creating a "total" row that sums up all cell values in a column is extremely fundamental capability that everyone uses in Excel.
I would propose a third possible use case:
The calculated column would be a running total based on another column
This would be helpful for lists showing potential work with an estimate of effort to get to that point (to assist with gauging resource needs, etc.).