I think it might be related more to what you are used to rather than one being more exceptional than the other. You are used to your wordy child, and probably have grown to see him as more "normal" than he is. Until someone points out to me that it isn't normal for a 5 year old to be tallying everyone's Yahtzee scores, I forget that my son is working 2-3 years ahead. I am used to my mathy son, so what amazes me are the highly verbal, talkative bright children I meet!
Sometimes it takes others to remind any parent just how exceptional their child is!
And I agree with the poster who said that mathy kids can be just as wordy/talkative as others, but it's more likely to be in the comfort of her/his own home. My son talks non-stop among our family and friends, but often acts like he is mute in public.
