This study investigates the neuro-mechanisms underlying mathematical processing in native (L1) and nonnative (L2) languages. Using functional magnetic resonance imaging (fMRI), Mandarin Chinese learners of English were imaged while performing calculations, parity judgments and linguistic tasks in their L1 (Chinese) and L2 (English). Results show that compared to L1, (1) calculation in L2 involves additional neural activation, especially in the left hemisphere, including the inferior frontal gyrus (Broca's area); (2) parity judgment engages similar regions for both languages, and (3) phonetic discrimination in L2 does not involve the perisylvian language (Broca's and Wernicke's) areas. These findings indicate that, calculation in L2, but not parity, can be processed through the L1 system, suggesting that the interaction between language and mathematics involves a specific neurocircuitry when associated with L2.