If you’re a student, a teacher or work in the STEM field there’s an app you should really check out: Calculator N+. A powerful scientific calculator app for your Android device, that’s free, open source, has no ads and will cover all of your math needs.
The power of the application is through the use of the Symja library. The results are displayed by Latex. The calculator does not show the steps to solve the equations, system of equations, derivative etc, only for the final result.
You can download Calculator N+ from Google Play or build it from source code.