Answer:
The answer to this question, as per research done on the new system of education, established since 2002, by President Bush, under the program No Child Left Behind, is, that gifted students are usually placed in a group, with peers of their same age, and similar overachieving skills, in what is known as Gifted and Talented classes (e.g AP classes). Otherwise, they are usually left to their own devices, while the teacher in a classroom focuses mostly on the under-achievers, as per the program, they must be brought to the level of the others.
In this the U.S system changed both for the better and the bad. The better because since the inception of the NCLB program, children with special needs, special disabilities, or from minorities who are showing less learning abilities than the others, are being focused on by teachers. However, the underside of it is, the overachievers, or those who are considered advanced students, or specially gifted. In order not to leave them behind, the AP program, and others like it, were created, to allow them to make use of their skills and abilities, without being refrained by their less skilled peers, and still share with others who show similar capacities.