Calculating Target Completion Date for Every Task on a List Based on a Fixed Deadline

We are opening up a new restaurant with an opening date of 11/30/15. There's a long tasks & assignments list on this spreadsheet. Column A has "Months Before Opening" for each task, but the "Target Completion Date" is blank. What formula do I need to put in to calculate the date that the number under Column A represents?

You can use this, say in B2 if A2 contains the months before opening:

=DATE(2015,11-A2,30)

Format as a date, then copy down as required.

Hope this helps.

Pete