Relative Dates for Smart Lists

shekala says:
I have a lot of Smart Lists that include relative dates. For example, tasks for the last 7 days. Is there a way to create a smart list that always includes the last 7 days of tasks without having to constantly update the Smart List? Currently I see I can use Today as a parameter, but can't make the after date something like "Today minus 7". Am I missing something? Seems like it should be doable.

(closed account) says:
This might help
https://www.rememberthemilk.com/help/answer/basics-search-advanced
addedWithin
addedWithin:"3 months of today"
https://www.rememberthemilk.com/help/answer/basics-search-advanced
addedWithin
addedWithin:"3 months of today"