Sum Date + Number

Hello .    I'm trying to create a new column with the following parameter .   I have 2 columns , "PO Delivery Date" that has dates and the "Projected Lead Time"  column has numbers , I would add the "PO Delivery Date" + "Projected Lead Time" and the result would come as a date.  Example:  "PO Delivery Date" = 17.02.2021 ( Date ) Column B = 15 (number) Sum of Two would = 04.03.2021