Creating a "Sum" Field in a BAQ or DASHBOARD

In the Dashboard module, I want to create a Line chart with the DATE on the X axis. On the Y axis there would be 2 fields that are summed up from other fields I have in the BAQ.

For example, I have 9 numerical fields on the Y axis. Instead of those 9 fields. I want 2 summed up fields. One of the want to sum up field #1,3,5,7 and 9. I want the other summed field to be from field #2,4,6 and 8.

How do I go about creating another field like that?