Calcado: Math Speed Trainer

Calcado is a math speed trainer built for anyone who wants to sharpen their mental calculation skills. No account needed, no internet required — just open the app and start practicing. The core mechanic is simple: a problem appears on screen, you enter your answer using the built-in numpad, and you move on to the next one. The app tracks your accuracy and response times so you can see how you improve over sessions. Supported operations cover addition, subtraction, multiplication, and division. You can mix them freely or focus on one at a time. Difficulty adjusts based on the number ranges you choose, so beginners and experienced mental calculators both have room to grow. Session statistics are stored locally on your device. You can review past performance, spot which operation types slow you down, and target your practice accordingly. There are no timers forcing you to rush unless you want them. A timed mode is available for those who enjoy the pressure, and a relaxed mode lets you focus purely on correctness. The interface is clean and distraction-free. Dark and light themes are both supported, and the app respects your system preference automatically.