Crystal Reports DIVISION BY ZERO

Message

     I have written a formula that shows percent of income.  I want to show a negative percentage if the job cost is more then the job billed.
if {@OVER/UNDER}> 0 then{@OVER/UNDER}/{JC_SUM.TODATE_REV}*100
else 0

this is the formula that puts a zero in the jobs that lost money but I need the negative percentage.

@over/under is job to date billed minus job to date cost. 