One way:

A1: 02.10.09

Add 24 hours:
A2: =A1+1

4-6 week date range:
A3: =TEXT(A1+28,"mm.dd.yyyy") & "-" & TEXT(A1+42,"mm.dd.yyyy")

8-10 week date range:
A4: =TEXT(A1+56,"mm.dd.yyyy") & "-" & TEXT(A1+70,"mm.dd.yyyy")

In article ,
Jschaeffel wrote:

I need to create a spreadsheet which has a beginning date, 02.10.09 and then
from that date adds, 24 hours, a 4-6 week date range, a 8-10 week range, etc.

Can someone help me get started?