Help with Formula to calculate milestone date

[MollyM]

Please help I need a formula for reoccurring seasonal milestones.  We have seasonal launch dates and milestones in each season that occur at intervals;  -130 wks, -80 wks, -56 wks.  I want to calculate the due date of the milestone based on season launch date  & milestone -wks (-50wks) to generate the due date for that milestone.   Please help! 

[TheTimeSavingCo]

This field deducts 130 weeks from the "Date" field, does this look right?

If so, the formula is

DATEADD(Date, -130, 'weeks')

And so you can try:

DATEADD(Date, {Weeks from launch formula}, 'weeks')

[MollyM]

thank you for your reply, unfortunately it still not working.  I want to calculate the due date by taking the season start date field (MM/DD/YYYY) and subtracting a number of weeks (-130, -53, -35) for each record to come up with the due date. Does Airtable formula not recognize my field # wks -130 ( or any number of week) and able to subtract that number of weeks from the season start date?  

[Alexey_Gusev]

Hi,
The second @TheTimeSavingCo formula should work. Formula must include information - which unit you want to add/subtract, so instead of 'date' you should type 'week' or 'weeks'
Also, you should remove minus, otherwise you get   Date  -(-130) weeks  so it will add weeks instead of substract.
Of course, you should insert your field names,  Season Launch, Weeks from launch

[MollyM]

I adjusted the formula in these two version and getting problem message and then #error?