Agreed, as a number it's not terribly useful, and in fact counterproductive for the reasons xlnt describes. Obviously you probably don't want to tell your son

Agreed, as a number it's not terribly useful, and in fact counterproductive for the reasons xlnt describes. Obviously you probably don't want to tell your son that, but as gojomo cautions, you might not want to praise him for it, either. (Edit: That is, if you do offer praise/encouragement, you'll want to do so in a way that avoids giving him false hopes that his number will become the next googol.) The thing is, simply naming a number isn't a great achievement, not even on the part of the mathematician's nephew who came up with 'googol'. It makes for an interesting story, but the thought processes involved are about as relevant to thinking mathematically as naming a pet dog is to understanding canine biology. But the initiative to name things is certainly valuable, and well worth reinforcing. The trick here is to lead your son towards an interest in the properties of numbers and away from any potential delusions of grandeur dependent on being the next 'googol' kid. Alternatively, or in concert with emphasizing the properties of numbers, you could also interest him in the properties of language and word construction, which he seems to have an aptitude for. Granted, your six year old would be pretty exceptional if you could get him interested in either!