The relatively weak visual-spatial skills made me doubt DS' math abilities even though he assimilated arithmetic skills early on with sporadic question/answer interactions rather than active teaching of math curriculum. His verbal ability, on the other hand, was undeniable. For example, he has always been articulate and able to read high-level text and explain complex concepts in a succinct and clear way,
These are good points, Polarbear. It's not acceleration just because he is able. Learning only a couple of new things all year last year was painful for him. The fact that he brought up the issue voluntarily out of the blue over the summmer(after a few similar comments during the year) led me to believe that he wanted me to fix it. DS is happier in his current situation even with some of the inevitable attendant difficulties. His "passion" for math is hard to gauge. Out of the blue, he may come up with some interesting patterns inherent in squares or he'll start exploring Fibonacci nubmers but he is really interested in lots of science and history stuff and just trivia in general.