A free program for Android, by Sergey Solovyev.

What is Calculator++?

Calculator++ is a free and open-source application for Android. It is a versatile and powerful calculator app. It can work as a standalone application or be used as a widget on your home screen. You can use it to calculate, plot, and save your results in a variety of formats.

It supports a wide variety of built-in functions. You can add your own functions and assign them to different buttons. This way you can easily calculate any mathematical expression or solve any algebraic equation. You can also use the built-in functions to perform arithmetic operations and mathematical calculations.