CalcTastic Scientific Calculator is a feature-rich scientific calculator with years of refinement and thousands of satisfied users. Choose from 5 different themes, a configurable display and your choice of operation, Algebraic or RPN. CalcTastic Scientific Calculator is FREE but comes with many great features including a Unit Converter, Fractions, Complex Numbers, Advanced Statistics, History & Memory Registers and a full-online Help Section. If you find CalcTastic Scientific Calculator useful, consider the PLUS version ($1 USD). The PLUS version also includes Polar-Form Complex Numbers, Landscape Support, 7 Additional Themes and a Full-Featured Programmers Calculator. GENERAL- Algebraic, Sequential or RPN input methods- Hybrid Prefix and Postfix notation. Expression or Stack Display- Expression History with 20 records- Calculator Stack with 50 registers- Memory with 10 registers- 5 high-quality themes- Copy and Paste- Configurable numeric display (decimal point and digit grouping) - Intuitive long-click feature removes the need to press SHIFT- Easier to use than an HP 11C / 15C SCIENTIFIC- Rectangular Form Complex Number Support- Real, Imaginary, Magnitude, Argument and Conjugate functions- Fractions and Fraction Calculations- Convert Decimals to Fractions- Degree, Minute, Second Support- Standard, Scientific, Engineering and Fixed Decimal Notations- Configurable Precision from 0 - 12 digits- Table of 44 Physical Constants- 289 different conversion units across 18 categories- Trig functions in Degrees, Radians or Grads- Hyperbolic Trig functions- Natural and Base-10 Logarithms- Percent and Delta Percentage- Remainder, Absolute, Ceiling and Floor operationsSTATISTICAL- Factorial (not integer limited) - Combinations and Permutations- Random Number Generator- 15 Single-Variable Statistics commands operate on all stack entries- Quantity, Min, Max, Range, Sum, Median- Arithmetic Mean, Geometric Mean, Mean Squared- Sum Squared, Sum of Squares of Variance- Sample Variance, Sample Standard Deviation- Population Variance, Population Standard Deviation.