Organization and structure can help. A specific time and place should be set aside for homework assignments, and let your child know you are going to stick to the plan. Sometimes your child's best time for doing assignments is not your best time to work with him. Whenever possible, work during your child's best time. If he is less frustrated, it is likely you will be less frustrated as well.
Tools can be especially helpful for children with a learning disability.
A typewriter or word processor can end the constant frustration of a child who has trouble with his penmanship. A word processor with a spell checker can make life a lot more pleasant for a child with spelling disabilities. A calculator can be a source of joy to a child with math problems. Assign your child a place to keep his schoolrelated materials-his books, his homework, school notices, lunch money, supplies, etc. Mornings will run more smoothly if all his things are kept in one place.