Dr. Cristina M. Dube has co-developed Math Castle, a research-based math-fact fluency app, with young software developers Christopher and Zachary Turner, ages 12 and 9. Drawing upon 40 years of experience in mathematics education, Dube designed the app’s content and 93 carefully sequenced developmental levels. Math Castle helps students see, hear, and handwrite addition, subtraction, multiplication, and division facts. The app launched in July 2026 and is available at MathCastle.app.