These days, a large percent of students are being diagnosed with ADHD or ADD. Most people would call it a "learning disability" but I firmly believe that if you suffer from one of these two conditions, you are not in any way disabled, no matter the level of your "disorder". ADD & ADHD are both issues that can be easily worked around in both a classroom or a home setting.
For example, if you are an elementary school teacher who has a student or multiple students, as the case may be nowadays, with ADD or ADHD you could simply have one of the subjects you teach daily, such as Reading or Science, have an "involved activity". Basically, what this would be is a game where at each cluster of tables, or at different locations throughout your classroom, you have a set of cards. Students should have to go from location to location to find the match to a card they were handed at the beginning of the game.
This gets everybody up & moving, as well as stimulates the brain more than a simple worksheet would, because the answer isn't automatically at hand.
For students who are in elementary school & having difficulty with math, I like to have a skit or a colorful presentation that can be used to help them better understand the material.
I would say that for parents who are having difficulty getting their child to focus on homework, because of ADD or ADHD, I would suggest having the child sit down in a room where there are no distractions; cover the windows with curtains so they can't be distracted by a bird outside, no electronics of any sort, & no extra people in the room. This will help ensure they get the work done.
Always look it over when they say they are finished. Make sure you check their homework/assignment logs to be sure they completed what they were supposed to. If your child still has difficulties focusing, go so far as to use devices that the internet now gives us, such as Quizlet.com. Make flash cards & review them with your child.
ADHD & ADD are not easily overcome in a classroom or home environment but it can be done. It just might require a little extra work for everybody involved.