1848-1925 510 arithmetic child childpsychology counting cross-culturalstudies exploration foundations geneticpsychology gottlob history infant infinite juvenileliterature learning mathematicalability mathematics mathematicsfrege nonfiction numberconceptinchildren numbers numbertheory numeration philosophy psychologicalaspects psychologicalaspectsofmathematics psychology real socialaspects sociologicalaspects sociologicalaspectsofmathematics statistics studyandteaching studyandteaching(elementary) symbolismofnumbers telescopes toyandmovablebooks yagwoia(papuanewguineanpeople)