You can add a new data series as a column that is calculated from the values in other columns. Calculations can only be added as columns, so before you can create your table / chart output you must add data type as a column:
For example if you wish to see the difference between planned and actual billing in a period you can add the normal data series' for billing plans - planned value, and sales invoices - invoiced amount. To add a calculated column that is the difference between the two just click to add a calculation.
Notice that the data series have been given an alphabetical reference:
So in this example the calculation you would enter is A-B. Just enter that into the box to the right of the new calculation series, and give the new calculated column a label:
Any arithmetic formula can be entered, so multiple data series can be added togther, or percentage calculations can be performed:
A-(B+C+D)
A/B*100
(A+B)/C*100