Like many pre teens, you son has skills which require quick responses such as games and the computer. These tend to appeal to this age group due to quick screen changes and visual affect. In order to provide a more successful work skill, be sure he is not hungry, rested, and can do his homework in a place without distraction e.g. no music or tv (including IPods). Take frequent breaks and be sure the study surface is free of clutter.
At the age 7-9, many bright males show Attention Deficit Disorder Inattentive Type. They are experts at things that show rapid change such as video games but do not have classic concentration to achieve homework as we have known it for a century.
Good luck but talk to his teacher to see if she/he has some suggestions also.
Wayne Yankus, MD, FAAP
expert panelist: pediatrics
Sometimes it is difficult to concentrate on something that doesn't interest us. Its important to keep the learning fun and engaging so that he can focus and learn. Keep each task at no more than 20 minutes. Have him also change locations frequently. Standing, doing some yoga poses or just standing and stretching between activities will also refuel him. Also set very short goals for him. If he can get through 20 minutes of homework reward him with outside playtime for 30 minutes. When children get fresh air and excercise they are better able to sit and concentrate. Do not push homework longer than an hour. At this point you are just wasting his time and your time. There isn't any learning going on if you are both feeling upset.
We in our house choose a particular time and place of study. This study time is followed by a very interesting play time (games, TV). This works good. If my child is more disturbed then we both work together.
Picking perfect time for concentrating on is as imperative as picking the right place. I lean toward learning around evening time as there is no unsettling influence around then you can pick your favored time like early morning, etc..