The research project, conducted by Eileen Baschek at Justus-Liebig-University Giessen, Germany, explores the impact of a bilingual PrimarWebQuest on the mathematical and linguistic learning of primary school students in Germany. The study focuses on the measurement of lengths, particularly the comparison between the US standard system and the metric system, which provides an opportunity for intercultural learning. Bilingual education in Germany involves teaching subjects in a different language for a fixed period, enhancing both linguistic and subject-related learning. The research design includes two small groups of 4th-grade students from a bilingual school, where mathematics is taught in English or German. The PrimarWebQuest aims to familiarize students with the US standard system and develop conversion skills between the two systems. Data analysis uses interaction analysis to examine how students negotiate and create shared meanings. Preliminary results will be presented, highlighting the students' understanding and development of mathematical concepts and language skills.The research project, conducted by Eileen Baschek at Justus-Liebig-University Giessen, Germany, explores the impact of a bilingual PrimarWebQuest on the mathematical and linguistic learning of primary school students in Germany. The study focuses on the measurement of lengths, particularly the comparison between the US standard system and the metric system, which provides an opportunity for intercultural learning. Bilingual education in Germany involves teaching subjects in a different language for a fixed period, enhancing both linguistic and subject-related learning. The research design includes two small groups of 4th-grade students from a bilingual school, where mathematics is taught in English or German. The PrimarWebQuest aims to familiarize students with the US standard system and develop conversion skills between the two systems. Data analysis uses interaction analysis to examine how students negotiate and create shared meanings. Preliminary results will be presented, highlighting the students' understanding and development of mathematical concepts and language skills.