Why is it that when you have less than one of something, that something becomes plural? What do I mean? Well if you have 2 apples sitting on your desk, the apples is plural (you have MORE than 1) with an ‘s.’ This is obviously correct. If you have one apple down your pants, the apple is singular, because, well you only have a single apple (and I am talking apples here, not nuts). But if suddenly you discover that you have 0.5 apples up your sleeve, you are back to using the plural form, apples. Why? Physically you have less than one apple, but Grammar says you do not (apparently Grammar ain’t no math wiz (but that’s okay because Math don’t know squat ‘bout grammar.). To throw a nice little monkey wrench in the mix, if you rephrase your statement to say you have half an apple in your eye (which may cause you significant pain and inflammation) you’re back to using the singular for of apple, but only because you placed the single identifier (an) in front of the word apple. If you only have 0.159 apples baked in a pie (which I don’t think would taste very good for an apple pie), who is going to want to say, “My pie only uses one hundred fifty nine thousandths of an apple!” when you can say, “point one five nine” instead? Most people can't even do that kind of math!