Mathematics education researchers examined teacher practices that support students who have historically been marginalized and have underperformed in school. These efforts have led to much discussion about how to incorporate culturally responsive pedagogy (CRP) theoretically and pragmatically. Many teachers want to develop and implement more practices that align with CRP but, in some cases, find it difficult to do so. More exploration of such cases has been recognized as a site for continued research. Researchers have used an identity lens to understand better why some teachers choose to identify as culturally responsive while others struggle to do so. One tool many researchers use to understand identity is Wenger's (1988) communities of practice and modes of belonging. Under this framework, it is essential to consider how a participant in a community of practice engages in the practice, imagines the bigger community practice, and aligns with other participants. Understanding the interaction between the three modes of belonging illuminates how participants frame their work and the tensions they may experience. This study used the communities of practice lens to understand better the intricacies of how four K-12 teachers identified with and made sense of their culturally responsive mathematics teaching (CRMT) practices. The analysis allowed me to view how each teacher framed their CRMT work into what I call their umbrella. Each teacher's umbrella bounded what they considered to be culturally responsive practices. The analysis also unveiled tensions teachers experienced when attempting to use their umbrellas. The tensions prevented the teachers from recognizing their CRMT practices. Sometimes, these tensions were connected to the teachers' racial identity, geographical location, language learning experiences, or math experiences. The findings describe each of the four umbrellas using words that each participant kept coming back to. Each umbrella showed what the teacher included as authentic CRMT practice and what they felt was more superficial. Sometimes this aligned with research or other teachers' ideas of authentic practice, but not always. All four teachers recount tensions they feel when trying to engage, imagine, or align as they identify with CRMT. The study has implications for how pre-service teacher education, institutions, and professional development could better support teachers' work in identifying with CRMT. The study also has recommendations for future research as it continues to understand and support the movement toward more critical and authentic CRMT practices. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]