The intro to the Standard states: “Understand a fraction a/b with a > 1 as a sum of fractions 1/b.” I had some trouble understanding what the intent was here, until I put it to myself this way: “… as a sum of unit fractions equal to 1/b.” Still, I felt that this was not precise enough.
Finally, I realized that what was missing was the indication that a and b have to be whole numbers greater than one. Now, I realize that most 4th graders are going to think only of whole numbers, but with the CCSS trying to build understanding from the earliest age that can handle the concepts, I think that this needs to be a specific, clearly delineated way to introduce unit fractions as building blocks.