If you want to compute with values that are the result of an aggregation, then you can
create calculations based on measures.
For example, you can create a calculation by adding a fixed value to a measure. The following
example adds 1 million to the Total Claim Amount measure.
You can use a calculation based on measures only in the dashboard where you created the
calculation. Calculations are not stored with the data source.
Procedure

In a dashboard, click a visualization that contains a measure column.
 Click the Fields panel to open it.
 In the Fields panel, from the measure context menu , click Create
calculation.
 Specify a name for your calculation.
 Define the calculation by using the appropriate mathematical operation, which can be
addition (+), subtraction (), multiplication (*), division (/), percentage (%), or percentage
change (% change).
Note: If you want to define the calculation by using the Cognos Analytics expression editor, click
Use calculation editor.
 Use the Calculate after aggregation option to set whether the
calculation is run before or after the data aggregation.
 Click OK.
The calculation is added to a slot in
the visualization as a new measure. This does not have to be the same slot as from where you created
the calculation. If you want to add the calculated measure to the slot you created the calculation
from, then drag the calculated measure to that slot.