not if you are just displaying it.
If you would like to use it somewhere else as a string you would assign it.
CR will display the last row of a formula, so no assignment is necessary. In addition, you can use this fact to 'hide' output of a formla...the formula can do whatever you need it to, but if you don't want to see any results on the report, just put "" as the last line, and for all intents and purposes the formula is invisible.
You should be able to format the field as well in the Edit Object for the cell.
Glad I could help