I think you misunderstood my example. My point was that knowing that there is 5 1/12 oranges (as opposed to 5) is the important precision, and it works logicall

I think you misunderstood my example. My point was that knowing that there is 5 1/12 oranges (as opposed to 5) is the important precision, and it works logically to a child's mind. It's quite a bit more complex to expect the child to discard the 1/12 and suggest there are 5 oranges. It's not that the 1/12 is useful for anything, it's the fact that it exists, and is accounted for.