They might talk too much or fool around too much which gets them in trouble with the teacher. Or they might disrupt other kids around them, so those kids can't do their work and end up getting mad at them. Other kids don't get hyper in school, they mostly have trouble paying attention to their work or to the teacher. This is called being inattentive. It can also help for the student to review instructions on the board, or to raise their hand and ask the teacher if they forget what they're supposed to do.
Some kids have trouble with organization.
They don't remember which assignments they're supposed to do, or just forget to take their homework and supplies home with them. It can really help to use an assignment notebook and write down every assignment when the teacher gives it. At home it helps to have a regular study time set aside, which is used only for doing homework and studying. Many kids think it's a great idea to have a separate folder for each subject, and even use a different color folder for each subject. Many kids with ADD are very good students, who get all their work done and get good grades.