Sharp Digit Dojo

Sharp Digit Dojo is a math training app built for anyone who wants to get faster and more accurate with mental arithmetic. No account needed, no internet required — just open and practice. The app covers four core operations: addition, subtraction, multiplication, and division. Problems are generated on the fly across adjustable difficulty levels, so whether you are brushing up on basics or pushing your limits with larger numbers, there is always a challenge waiting. Answers are entered through a purpose-built numpad designed for speed and accuracy. The layout is clean and distraction-free, keeping your focus on the problem in front of you. Each session tracks your results locally — correct answers, mistakes, and response times. Over time you can see where you are improving and which operation types need more attention. All history is stored on your device and never leaves it. A few things that make daily practice easier: a configurable session length so you can fit a quick drill into a spare five minutes, per-operation difficulty controls, and a straightforward stats view that shows streaks and accuracy trends without burying you in charts. The app follows your system navigation and respects safe area insets, so it sits comfortably on any Android device regardless of screen shape or gesture navigation setup. There are no ads, no purchases, and nothing to sign up for. Sharp Digit Dojo is a focused tool — open it, work through some problems, and close it when you are done.