My products are duration based.  I am working in Quotes.

I have a product that lasts 30 days, 90 days, or 365 Days
i have created a duration field where the 30, 90, or 365 will go

I have a Start Date field where the product start date will be entered

and I want to calculate an end date

So Start Date + Duration = End Date

I have tried: Adddate((${Quoted Items.Start Date})+(${Quoted Items.Duration}))

and: Adddate(Datepart${Quoted Items.Start Date}+${Quoted Items.Duration})

any ideas?