Two-Way Immersion (TWI) programs have demonstrated positive outcomes in students' academic achievement in English, yet less is known about content teaching and learning in the non-English language in these programs. This study uses math instruction as a lens to identify pedagogical strategies and challenges in the teaching of math in Korean to bilingual students. Analysis of classroom interaction data shows that math instruction in Korean followed the curricular sequence and pedagogy designed for teaching math in English, leading to missed opportunities for more effective content pedagogy that utilizes language-specific characteristics inherent to the grammatical structure of Korean. This study highlights the need for not only language-specific content curricula but also language-specific pedagogical knowledge and training for TWI teachers, in particular in the non-English language of instruction.