Solvable is an Android app developed by Schramkowski LLC that offers a step-by-step math solver and graphing calculator in an easy-to-use form factor. The app has a clean interface with a convenient keyboard and scientific functions like trigonometry, exponential, statistics, and more. It recognizes constants like e, pi, and allows you to reuse formulas by substituting different values.

One of the standout features of Solvable is its large interactive graphing window that allows you to graph up to 5 functions with touch-controlled scale/pan. You can find function roots graphically and switch between dark and light themes. The app also has a detailed how-to-use guide and can display up to 15 decimal places.

Solvable works completely offline and offers premium features like solving equations with step-by-step guides, simplifying expressions, and plotting functions with multiple variables using value sliders. The app has some known issues like freezing while zooming in very far when using the graphing window and unexpected in-app keyboard behavior when using Microsoft SwiftKey.

Overall, Solvable is an excellent app that is perfect for students and professionals alike who need a reliable and easy-to-use math solver and graphing calculator.