Well, what answer do you expect? Would you believe me if I suggested that a healthy diet and regular workouts would solve your problem? You also have to brush your teeth at least twice daily and cut on spending time in front of TV or with earphones (except while jogging.)

Other than that, I think you have to do what you have to do. There is no other way. Except, perhaps, try to separate your efforts. School math aside, while working on it, try to think of what is difficult to you and work back from there. Get to the root of the difficulty and master it. Then reverse your way a step at a time. This should come on top of carrying on with you school assignments.