Please note that I'm not saying no drill ever. But in this context, I think that if a kid can do a whole bunch of division problems the first time out of the gate, he gets division. And maybe rather than fretting about whether he's doing enough work, maybe we should be taking it as a sign that he understands and we can move on.
I approach this question by moving on when my eldest understands the concept and can do a small series of problems without any help from me. I typically make increase the difficulty of the problems in the series. This helps catch little things, like place value in long division or remembering sign issues when moving numbers across the equals sign.
Then I'll give him a few of the same types of problems a week later. Can he still do them? If yes, great. If not, I go over them with him, which usually involves relatively quick reminders (but not always).
Then I'll do a review after maybe 2 weeks, and so it goes, with the time periods increasing.
Val
