Dates in workflow

I am attempting to kick off a workflow by having a custom date field be less than or equal to Now - 7 days. The workflow works when I make the condition be my date is less than or equal to now but doesn’t when I make it less than or equal to Now -7. Is this because I have misunderstood the number? In Excel, the Now()-7 gives ne the date seven days ago.

Daniel

I gound the answer. The dropdown after the seven that said none can be changed to Days, Weeks or whatever. Whew!