Background: Mindfulness practices enhance executive function skills and academic achievement, spurring interest in integrating mindfulness interventions into education. Embedding mindfulness practice into a digital math game may provide a low-cost, scalable way to induce mindfulness and boost game-based learning, yet this approach remains unexplored. Objectives: We investigated the learning benefits of integrating mindfulness exercises in a digital math learning game and examined how students' trait mindfulness might moderate the outcomes. Methods: Two classroom studies were conducted with 404 5th and 6th grade students from six public schools in the U.S. (n[subscript Study 1] = 227, n[subscript Study 2] = 177). The two randomized controlled experiments assigned students to one of the three conditions: passive control (playing the digital learning game "Decimal Point"), story-enriched active control, or mindfulness-enriched condition. Trait mindfulness, learning gains, and in-game problem-solving (including problem-solving duration, error count and correctness after reminder) were assessed. Study 2 included a manipulation check to better understand the effects of the mindfulness intervention. Results: Findings showed no significant differences in learning gains, problem-solving duration or error count among the conditions. Students' trait mindfulness did not moderate these outcomes. Mindfulness reminders in the mindfulness-enriched game led to more correct answers after errors than jokes in the story-enriched game. Study 2 revealed that we failed to induce higher state mindfulness through the mindfulness inductions. Conclusions: Mindfulness prompts could be especially beneficial for students experiencing frustration during gameplay, warranting more exploration for digital game-based instruction. We highlight barriers and future directions for fostering mindfulness through computer-based instruction in classrooms.