Features:

Direct formula input
10 constant memories
Variables
1 cumulating memory
Nearly unlimited nesting of brackets
Automatic bracket completion
Calculations in decimal, hexadecimal and binary number system - mixed number systems are allowed in one expression.
Display in decimal, hexadecimal and binary format
Edit expressions which have just been calculated
More than one expression in one input line
Program state (content of memories, input line, etc.) is saved at program termination
Intelligent error messages: after issuing an error message the cursor points to the error location
Plot and print function graphs (with labels for title and axes)
Logic operators: AND, OR, XOR, NOT
Square
Reciprocal
Square root, cubic root, root with random exponent
Powers to basis e, to basis 10 and random basis
Natural and common logarithm
Trigonometric functions and inverse functions
Three angle units: degrees, grads, radians
Constant Pi
Numeric integration (quadrature)
Random numbers
Absolute value
Step function
Minimum and maximum out of a nearly unlimited number of arguments
Factorial
Combinations and permutations
Conversion between rectangular and polar coordinates and vice versa
Conversion between decimal and sexagesimal system and vice versa

Plot functions:

Normal and parametric plots - may be used simultaneously
Labels for plot title and coordiante axes
Displayed function is automatically used as title (editable)
Linear and logarithmic units
Number of tick marks may be changed
Calculated expressions for all input fields, you may enter "2*pi" for example
Export to clipboard as metafile
Zoom function.
Coordinate window shows mouse position and function value.
Multiple functions in one plot window.