WolframAlpha
Covers Elementary math, Numbers, Plotting, Algebra, Matrices, Calculus, Geometry, Trigonometry, Discrete Math, Number theory, Applied math, logic functions, unit measures (bulk materials, paint, conversions).
MyScript Calculator
A handwriting recognition system allows users to write down equations and have the app calculate results. MyScript supports basic arithmetic, as well as percent, square roots, trigonometric (and inverse) functions, logarithms and constants such as pi and Euler's number.
Graphing Calculator
MathRef
Solve math problems more easily by browsing over 1,400 formulas, figures and examples. Also includes a unit converter, quadratic solver and triangle solver for quick calculations.
Mathway
A math learning aid that allows you to plug in equations and display step-by-step solutions to get to the final answer. Simply input the problem or import it using your camera; Mathway provides you with the answer and shows you each step of the solution to get there. Covering a range of topics from basic math to algebra, calculus and statistics, it's a useful study aid.
NOTE: The website MathWay can also be used on your pc (for free).
