@Willeke In the song "Six (My Favorite Number Is)" Bert says he spends "all afternoon" thinking about six. Given that, I think we might postulate hat 6 earned by "collecting or doing 6 things over the space of an afternoon".
http://www.metrolyrics.com/six-lyrics-sesame-street.html
http://www.metrolyrics.com/six-lyrics-sesame-street.html