Raddy,
I'll have to try for The Mislabeled Child book, tks. For awhile, I thought it was the Misdiagnosis book by James Webb, which was excellent as well.
I understand about the variation in performance. My son is exactly like that. He loved Ed Zacarro's Primary Math Challenge - he'd be doing wonders for weeks and then seemingly blank out on what to do on the same topic suddenly. I used to think it was "good days" and "bad days", and luckily, we didn't have the pressure of school back then.
In my son's case, I think he may have had gaps in his understanding. He's great with logic and thinking through each question, but he does stumble or gets tired sometimes. I used to think that he didn't need practice, but I'm realizing that perhaps he does need to, not in a drillish way, but in a as-many-interesting-problems-as-I-can-find sort of way. To this end, we're trying a mishmash of questions, from grade 4-6 (from Aleks to Singapore Math to a mathplayground.com) and some algebra when he feels like it. School doesn't allow for this sort of experimentation though.
