Adding expressions to the reports will enable the user to include calculated fields.
For example, you will be able to produce a 'Volunteers' report where you need to be able to calculate the value of a volunteer.
This means that they would need to multiply the number of hours worked against the value per hour.
Find the report to edit.
In the Report Builder, click Add Expression.
Add a title for the Expression in the Caption field.
Specify the Data Type (e.g. 'Text', 'Currency', 'Date' etc.).
Click the Insert Expression button and select the appropriate value from the menu.
Use the Insert Field button to add the fields to calculate.
Click OK.
The expression will now be added to the report.
Insert Expression can be used multiple times to create complex pathing and results. Such as using an IF statement to bring back multiple different sets of results depending on the starting data.