I want a validation rule on a field that only allows entry of whole numbers or numbers that end with .5. For example 0.5, 1, 1.5, 2, 2.5 etc This number sequence can go on into the 1000s.Also the field can not be Null or less than 0.5. So far I have; Is Null Or >=0.5 but I don't know how to get the above to work. Perhaps a input mask would work better?