Using SharePoint 2013, I have a list column of type Number, and I'd like to restrict it to either whole / half numbers, i.e. 0.5, 1, 1.5, 2, 2.5. But values such as 3.4, 2.6 wouldn't be allowed.
A choice column is unsuitable as the range users will input could go into the 100's.
Can I use custom validation on the column for this and if so how?