Difference Between 0CREATED_ON and Today's date

Hi Experts,

I am new to BW and I have to accomplish the following requirement.

We have a characteristic 0CREATED_ON and when the report is run we need to calculate the difference between today's date and 0CREATED_ON. Can you please advice on the best possible way to achieve the same. If it could be broken into the logical steps, it would be a great help!!

Thanks for the help in advance.

Regards

PG