how to use decimals in validation rules

Summary: I am trying to make a validation rule which throws a warning when a promotion is submitted without a pay change. When I use the validation rules tool in express mode it the condition field will only take a whole number. I need to use '0.0000' as the data check. When I enter this value it formats to '0' and the rule does not work. Is there a way to use decimals in the condition rules?

C

Version (include the version you are using, if applicable): 24C

Code Snippet (add any code snippets that support your topic, if applicable):