=LEFT(A20,4)+(--RIGHT(A20,LEN(A20)-FIND("/",A20))9)&"/"&(RIGHT(A20,LEN(A20)-FIND("/",A20))+3)-(--RIGHT(A20,LEN(A20)-FIND("/",A20))9)*12

and

=LEFT(A20,4)-(--RIGHT(A20,LEN(A20)-FIND("/",A20))<4)&"/"&(RIGHT(A20,LEN(A20)-FIND("/",A20))-3)+(--RIGHT(A20,LEN(A20)-FIND("/",A20))<4)*12

--
HTH

Bob

(there's no email, no snail mail, but somewhere should be gmail in my addy)

"renee" wrote in message
...
My sales training takes place on 2007/10.

How do I get excel to calculate in another column the 3 months prior to
this
date and the 3 months post this date.

i.e. 2007/09
2007/08
2007/07
2007/11
2007/12
2008/01