Addendum

I find it useful to tell my kids that if they are "remedial" in an important subject they will have to be prepared to spend MORE time, not less, working on the boring basics. If they can move faster they can get to the fun stuff faster. That way they realize that saying "I can't" doesn't save them any effort, and it helps me avoid the temptation to compensate for their weaknesses. But I have to keep reminding myself of this often. I also have to keep reminding myself that they are young and immature and what looks EASY to me may not seem so to them. I don't use Montessori, but I think that there's truth that kids need to not only learn a skill, but re-learn and over-learn it; it takes time for young ones to consolidate on fundamentals. There's definitely a give and take relationship going on there.