InfoPath Dev

I know that dates are difficult to manage in InfoPath with code and I am no coder but I dont understand why this doesn't work.

I have a date submitted [set as today() ] and a transaction date.  The date submitted cannot be greater than 100 days after the transaction date.

I tried a data validation rule that said if transdate is less than (datesub -100) and transdate not blank, pop a message. 

However I get the message for all transaction dates.

Am I missing something right in front of me?

 Thanks

I got it.  Had to use function Adddays.