My 6 years old DS is exactly like this - he does this with his teachers at school too, not just at home! We get regular updates in report cards about "lacking independence while working". While doing school homework or afterschooling, he asks me to check his work for every single line he writes. If I did not respond, he is off playing with something or other.
The reason my child is this way is because of several things - he was in a montessori daycare/preschool in his early years - and there was always someone who was with him interacting and helping and teaching - he even used to sit on the main teacher's lap while coloring and painting and writing. And he is extremely social and talkative and likes to have someone to chat with him while he works and feels isolated and lonely when alone at a desk. So, I stay close by and give him incentives for independent work - e.g. if he works without asking for help on 2 pages of his singapore math book and makes no mistakes, then he skips the entire chapter and moves on to the next chapter. That helps him overcome his natural impatience to seatwork as well as cuts down on the careless mistakes. I also give him a sticker on the pages he does without asking for help from me. And he will do anything to collect stickers
