Examining linked academic transcripts from urban community colleges and their feeder high schools, we identify math course-taking patterns that span sectors. We highlight stifled mobility and chronic repetition of math coursework in the transition to college, and we identify "math traps" from which students do not escape. Math mobility was limited, math repetition was rampant, and nearly half of students found themselves in math traps. All else equal, being trapped in math was significantly linked to race/ethnicity, suggesting that these forms of chronic math tracking across sectors expose previously undocumented forms of inequality in educational experiences.