The ultimate calculator: rotate your phone between a basic and a very capable scientific one (but you can lock it down to one, if you prefer):

In portrait mode, you have a basic calculator with:
- basic mathematical operations
- 00 and double-sized plus buttons
- normal and financial (two decimal digits) display
- percent, reciprocal, square and square root
- memory add, subtract, read, write, clear
- value added tax calculation
- currency conversion
- paper-like, scrollable multi-line display.

When you are in landscape mode, the calculator becomes a full-fledged scientific calculator with:
- seven modes: normal (decimal and fraction), engineering, scientific, fixed point, complex, programmer's, statistics
- true 128-bit decimal floating point calculations without rounding errors (retaining significant trailing zeroes)
- precision up to 32 decimal places, number range: 1e-6143 to 1e+6144 (as per the IEEE 754 standard)
- basic and advanced operations (modulo, power, root, exponential, logarithmic, trigonometric, hyperbolic)
- standard mathematical operation precedence
- trigonometric functions: arguments in radians, degrees and gradians, angle conversion
- random numbers
- infinitely nested parentheses
- advanced data entry: decimals, fractions, scientific, engineering (SI) prefixes (atto to zetta)
- sexagesimal calculation with degrees, minutes and seconds
- rectangular and polar co-ordinates
- memory functions
- complex numbers, absolute values and arguments, complex support for all exponential, logarithmic, trigonometric and hyperbolic functions
- programmer's mode: binary, octal, decimal, hexadecimal with logical and shift operations
- statistical mode: mean values, standard and popular deviations, various x and y summa values, permutations, combinations, GCD, LCM, prime testing, factorization

If you have a crash, please, send a report to the support address. This is the only way to fix it for you and for others. :-)