Information about the series: Language plays a central role in conveying mathematical content. For children who do not speak German as their first language or who have additional language support needs, this often lies at the root of seemingly mathematical problems. In response to this issue, eins-zwei-drei is the first teaching resource to consistently address it: It combines mathematical subject content with systematic language support, ensuring that all children meet the educational standards in mathematics. To this end, eins-zwei-drei provides child-friendly language models, systematic development of mathematical vocabulary, clear explanation phases for introducing new content, carefully formulated mathematical tasks that take linguistic stumbling blocks into account, extensive information on these stumbling blocks, as well as practical teaching suggestions in the teacher's materials.