The latest version of Numbers has a great feature called Smart Categories that are kind of like Excel's pivot tables. I'm using it to group a table by a label and then sum up spending and revenue numbers.
The next thing I'd like to do is calculate the ratio between these two, i.e. a new column that has the value
revenue / spending. How do I do this? If I create a new column, the only options are to use built-in summary functions (see below) - I can't enter my own formula.
Example of smart categories:
Options for "Ratio" column: