As a former nanny, I thought I'd share a couple of tips for children who have a difficult time focusing on their homework. This can be helpful for children with ADD or ADHD.
Tip #1: Homework should be done in a place that is comfortable but has the least amount of simulation, visually and audibly. A bedroom where toys are can be a distraction. I suggest you pick the barest room possible where no one is talking and where the radio, computer and television are all completely turned off. If you have two children, put them in different rooms. I've found that children find dining rooms generally boring, and therefore are less likely to look about so much and get up to touch things. If you have knick-knacks around, move them.
Tip #2: Limit the time your child spends on a homework task. If the math they brought home would normally take half hour for a child who can concentrate well, your child might need three 15 minute time periods. Use an oven or egg timer to count down the time. After 15 minutes, let your child take a short break. They can stretch, do jumping jacks, eat a snack or some other small respite. Do not encourage a board game or watching T.V. This break is only meant to be a breather. So they can learn to refocus. Do not get frustrated if your child has trouble with any of the 15 minute intervals. If need be cut down to ten minutes. It is far better to get something done in ten minutes, than for him or her get almost nothing done in forty-five minutes. It's not worth the aggravation. To either of you.
Remember if you're getting frustrated about the homework situation you're not adding anything positive to it. If need be go to another room, count to ten or twenty and calmly come back in and check on your child. If they're daydreaming, playing with their pencil, flipping on and off the light switch… gently remind your child to stay on task. (You can always tape the cover of your light switch shut.) If you would like, you can at another time though not a hectic one (you're running late for school), talk to your child about small rewards for staying on task. You can have a bag of marbles and every time your child focuses on their homework for 15 minutes they get to put a marble in a jar (5 marbles can equal a special game with you or 15 minutes of computer time). This means even if your child doesn't stay on task for all three 15 minute time periods, they're still rewarded for the one or two times they do. It gives them motivation and a positive outlook they can indeed focus. Do not reinforce that they can't focus. Most children can focus in varying degrees.
If your child is seriously struggling to get their homework done and can't, please talk to their teacher about shortening their homework. Maybe instead of doing 30 math problems, your child can do 10. I believe if your child is having a really difficult time focusing on their homework, there's a strong likelihood they're also having a difficult time focusing on their schoolwork as well. A conscientious teacher will pick up on this and want to work with you. If you don't have a teacher who will work with you I encourage you to meet with your principle. You're your child’s voice.
Point to think about: I know of lawyers today who didn't finish their homework back in grade school and junior high, who SOMEHOW managed to finish law school and pass the bar. The lesson here: Finishing grade school and junior high homework is not the be all and end all to your child's future. So stop making it like it's the end of world if they can't finish it; especially if they're trying to the best of THEIR ability. Please note how I wrote "their" ability and not "yours."