Free dreamcalc scientific calculator software for windows

A general-purpose scientific calculator that you can use as a computer-desktop calculator Java Scientific Calculator is a small, simple and easy-to-use Java-based application that represents a general-purpose scientific calculator which you can use as a computer-desktop calculator or in a web application.
In addition to basic arithmetic functions it provides trigonometric functions, logarithms, powers and roots, complex numbers, binary, octal, decimal and hexadecimal calculations, logic, scientific notation, memory, statistical funcions (mean, and population and sample standard deviations), permutations and combinations.
Java Scientific Calculator also supports editing and replay of input and copying of output to the (system) clipboard. You can resize the application to one of three sizes and use the keyboard instead of the mouse for all keys.
Java Scientific Calculator was originally designed as part of a web application to show how you can use a calculator to calculate confidence intervals. This is why it has statistical functions and behaves in a similar way to pocket scientific calculators.
System requirements:
- Java 2 1.5

English version.
Solves math expressions like: Sin(Pi)-Root(-8;3)+3
Creates users functions (e.g. surfaces, volumes, and so on). Publishes in Internet. Receives from Internet.
Program shows position of bugs in math expression made by user. Descriptions of bugs help solve a problem.
Prompter shows functions, variables, constants. Simply press SPACE key.
Exchange rates table and currency converter are update from Internet by one click.
Units converter makes easier to convert various units.
14 categories of units: length, temperature, pressure and so on.
Creates users variables.
Numeral systems: binary, octal, decimal, hexadecimal.
Measures of angle: radian, degree, gradus.
5 sets of keyboards configured ba a user.
3 calculators - user can calculate three various math expressions.
Button Undo and Redo.
History of math expressions.
Comprehensive Help.

ReactOS Calc is a scientific calculator that has been written with the purpose to be a clone of calculators included into MS Win32 operating systems. It has a similar user interface and keyboard shortcuts.
ReactOS Calc is a program for evaluating mathematical, financial and statistical calculations.
Main features:
- Internal precision with 17 decimal numbers.
- Robust RPN (reverse polish notation) engine which allows a virtually unlimited number of arithmetic and algebraic sub-expressions.
- Two different interfaces: standard or scientific.
- Many common arithmetic, algebraic and statistical functions are included.

Scientific and Business RPN Calculator with :
- mouse operated, with mouse "keypad"
- standard functions
- trigonometric functions
- finance functions
- RPN (Reverse Polish Notation) mode
- infinite and circular stack
- registers display (stack, 11 memory regs, finance registers)
- display intermediate keystroke and results, status bar
- navigation through history for entry correction and replay (with operation delete, skip, ... options)
- save and reload your calculations to file
- multiple auto-save on exit options
- print
- quick help
- ...
... unmatched features free for ever (no trial period, full version for free)!