This class asks two big questions: what can mathematics offer social justice movements, and what does a social justice perspective have to say about mathematics? Almost every social issue, from environmental justice to gerrymandering to police brutality, has a quantitative aspect: the first main thread of the course investigates the mathematical tools and ideas that are necessary to understand, critique, and make progress on these issues. From another angle, mathematics is often portrayed as objective, value-neutral, and apolitical–but as a human endeavor, it is also culturally specific, requires choice and judgment, and can actively contribute to systemic racism and other chronic injustices. As a W course, we will also focus on communicating mathematical ideas to a variety of audiences through writing, with an emphasis on the feedback-revision cycle.