The opposition between quantitative sciences and the humanities is a well-known problem of cultural debates, along with its reflection in the conflicting approaches to digital humanities. As the emphasis has moved from long-standing scientific methods of quantification to the overall digital turn of everyday life, this process sheds light on the varying sociocultural conditions for calculations in modern societies. Consequently, numbers cannot be conceived as inherent properties of things by discovery through experimentation and explanation: this essentialist conception seems to originate in a misunderstanding of nineteenth-century scientific research and its claim of objectivity. Rather, quantification and the cultural matrices of calculation build a raster image serving as an interface between world and mind. In this broad sense, everyday life is deeply pervaded by numbers. Moreover, the ability for calculations cannot be treated as a uniform skill any more. Instead, it varies in accordance with different cultural forms and functions. Number-based practices are also represented widely in modern literature and in non-literary works, such as being in the letters and diaries of many writers. The essay is thus intended to analyze and compare the forms of calculation in the novels and diaries of some East Central European writers—such as Kafka, Kosztolányi, Musil—who thrived in the first decades of the twentieth century. In so doing, it describes three models through which calculation as a cultural practice enters the field of literature.