Commercial and financial mathematics in the Lutheran parochial schools of Rio Grande do Sul in the first half of the 20th century

Abstract The article discusses how commercial and financial mathematics was taught in the Lutheran parochial schools of Rio Grande do Sul, during the first half of the 20th century, through the analysis of the Segunda Aritmética and of the Terceira Aritmética of the Concórdia series, edited by the Lutheran Church for their schools. The methodological support is grounded on cultural history and on content analysis. The Missouri Synod, currently the Evangelical Lutheran Church of Brazil, began its mission in the German colonies of Rio Grande do Sul in 1900, by founding religious congregations and parochial schools. These schools were inserted in a missionary and community project that sought to teach the mother tongue, mathematics, and cultural, social and religious values. Commercial and financial mathematics was approached in a contextualized manner in relation to the reality of the students, encouraging the development of the proportional thinking, of the correct calculation of return and debt values, and of the study of financial investments involving simple interest.