The RPNcalc 15 is a full featured high end scientific RPN calculator with support for complex numbers and matrix math. All Features: at a glance: ? Display & Keyboard: ? Fixed number format ? Scientific number format ? Engineering number format ? Backspace ? Math: ? +, -, ×, ÷, %, 1/x, root, x^y, pi, ln, log, e, ...and many more ? Integer truncation and absolute value ? Trigonometric and inverse trigonometric functions ? Hyperbolic and inverse hyperbolic trigonometric functions ? Trigonometric modes (degrees, radians, grads) ? % change ? Advanced Math: ? Solver / root finder ? Numeric integration ? Complex numbers ? Matrix operations ? Statistical: ? Mean standard deviation of 2 variables ? Summation ? Random number generator ? Linear regression ? Correlation coefficient ? Factorial ? Gamma ? Combinations and permutations ? Scientific and Time: ? Polar and rectangular conversions ? Decimal hrs / hrs.min.sec. conversions About RPN: The Reverse Polish Notation is a mathematical notation in which operators follow their operands. It does not need any parentheses as long as each operator has a fixed number of operands.