For students, engineers, scientists or people who fondly remember classic calculators, Halcyon Calc is a great application for manipulating numbers and even symbolic expressions.

Features:
- Use this calculator on an iPhone, iPod Touch or an iPad
- Use your finger to quickly scroll through the stack to review intermediate results
- Copy and paste support
- Over 225 built-in operations, including trig, logarithms, real functions, complex operations and more
- Allows you to work with real, complex and integer numbers.
- Real and complex numbers can be displayed in standard, fixed, scientific and engineering format
- Use over 120 built-in units to perform unit conversion or create your own units if the one you want is not already there
- Integer numbers can be displayed in decimal, hexadecimal, octal and binary bases
- Work with real and complex matrices and vectors.
- Enter symbolic expressions and solve them for different values. Even better, solve quadratic formulas, collect and expand factors and terms, find minima, maxima and roots of any expression.
- Plot symbolic expressions in X/Y coordinates. Pan the coordinate space by dragging the plot in any direction. Zoom in and out using a pinch gesture.
- Determine symbolic derivative, taylor series or numeric integral of an expression.
- Store numbers, lists, strings and expressions in symbols. Create hierarchies of symbols to allow you to organize your calculations.
- Create sequences of calculator commands into programs, creating your own operations which you can then include in expressions.
- Store statistical data and calculate totals, averages, standard deviations, linear regressions, etc over that data.
- Calculate the probabilities associated with standard distributions like the normal, F and T distributions.