This diploma thesis deals with the study of mobile operating systems and their use in mathematic lessons at school. The aim is to give a summary about actual insights referring to the use of smartphones or tablets in school. Therefore topics focused on "learning" are covered. To form an opinion about the situation in a classroom, the second part of this diploma thesis includes results of a survey, which was accomplished in a technical school in Vienna. The survey shows the qualifications, the personal connection to the smartphone and possible ways for the use in school. The third part of this diploma thesis includes a list of applications with different mathematical topics for the use in school lessons.