Formula properties are derived from numeric or date card properties. They allow you to create automatically computed values, reducing opportunities for inconsistency.
You can create an aggregate property based on a formula property. Beginning with Mingle 3.0, you can also use aggregates in formula properties.
A simple example is calculating the end date of an iteration based on the start date and the length of the iteration in days. Here "Start Date" and "Iteration Length" are properties assigned to the "Iteration" card type.
The formula definition might look like:
"Start Date" + ("Iteration Length" - 1)