This is so true in our household, too. Workboxes have also been a lifesaver. We don't necessarily go in order, so the kids know that if they need to wait for me, they can find their other assignments in the boxes and are welcome to work on them. The incentive is that the sooner they get their work done, the sooner they can go play. If there just isn't anything they can do without me, they will often go outside and play until I'm available.