Calculate scores

How can I make composite scores by adding the responses from multiple questions?  For example, items 1 & 2 add up to Score A, items 3 & 4 add up to Score B, etc.

Then, how can I format my report based on those composite scores (A,B,C)?  Is there something built in or do I need a plugin to do the calculations?

You can assign calculation values for each of your questions that you need to add.

How-to-Assign-Calculation-Value

Then use Form Calculation widgets to do the actual computation.

How-to-Perform-Form-Calculation-Using-a-Widget