The filter created in the previous task as well as the Milestones and Completed Tasks filters are examples of what I call static filters . These are filters that always have the same criteria. However, you can also have filters like the Date Range filter or the Cost Greater Than filter, which are examples of what I call interactive filters . These filters ask you for input when you apply them, and then filter the view based on that input. In the case of the Cost Greater Than filter, you are prompted with the following dialog.
You enter a cost value in the box and then Project filters the view to show only the tasks that cost more than the value you entered.
Creating one of these filters for yourself is pretty easy. The best way to explain this is to show you the Filter Definition dialog for the Cost Greater Than filter.
Select the Value field.
Notice that instead of a real value, there is a text string inside quotes: "Show tasks/assignments whose cost is greater than:" followed by a question mark.
By putting a string in quotation marks followed by a question mark, you are telling Project that the filter should ask the user applying the filter for the data that will be used as the value for the filter.
Select the Value field. 
Notice that instead of a real value, there is a text string inside quotes: "Show tasks/assignments whose cost is greater than:" followed by a question mark. 
