ACalc

ACalc is an all-new calculator app optimized for scientific and engineering use. It is easy to use, and has a multitude of features. Supported on Android phones and tablets.

Features include:
-Pretty-printing
-Algebraic Simplification and expansion
-Expression evaluation
-Variable storage
-Statistics
-Probability
-Derivatives
-Matrices
-Complex numbers
-Equation Solving

Terms and conditions
ACalc does not come with any warranty. It is the responsibility of the user to ensure answers provided by ACalc are reasonable and as expected, accounting for any floating point rounding errors which may be present in results. You may not reverse engineer this software.
Added an equation solver and fixed a few issues.