In this example we want to calculate and display the remaining time (in days) of issues and subtasks in an epic.
For this we need a calculated number field. The configuration will look like this:
Text to be parsed is: sum(fieldValue({00024}, issuesUnderEpic() UNION subtasks(issuesUnderEpic()))) /480
The display format configuration is shown in the following screenshot.
Text to be parsed is: ###.## d
This is done for displaying the remaining time in days.
Adding the custom field to the issue screen will look like this: