I am seeking to gain a better understanding of constructing formulats using
dates and time.

a) In the formula below I enter the start date in Cell A2
b) Number of weeks in B2
C) +/- days offset in C2

=DATE(YEAR(A2),MONTH(A2),DAY(A2)+7*B2+C2)

Question 1
How do I modify the above formula to count in months instead of weeks?

Question 2
Is it possible to adapt it so I can choose the period to count in:
For example: Years, Months, Weeks, Days, Hours, Seconds

Any examples would be appreciated
Thanks