Conditional formatting: cell value equal to multiple numbers

Using conditional formatting to format cells with color works fine if I want to do a single value, but now I'm in a situation where I'm looking at 40 different values that appear multiple times in a pretty big spreadsheet. Is there a way I could enter all the values into the field rather than repeating the operation 40 times? I would imagine that I could use a comma to do it but it didn't seem to work so maybe I made a mistake?