Subtract days from a variable holding date

Hi,

could someone help on this..

I have a date in variable

procdate="05/30/2009"

I would want to Subtract it with 3 or 4

search the forums ...

http://www.unix.com/answers-frequently-asked-questions/13785-yesterdays-date-date-arithmetic.html

well That form couldnt get my requirement..

any other help