How to update text in calculated column for specific date range

Hi, can u plz help...i need to create a calculated column using DAX and update some text value for a specific date range where the date column exisits say order date in Sales table. for Example update as "Last Week" when a date column lies in the date range of last week. when a slicer(just created a table with columns "Last Week","Last month","Last Year" and included that in Slicer) is selected as "Last week".