HOW TO WORK THIS THING: For the most part, this calculator can be used just like ones that you have seen before, but some things may require explanation: You can use your keyboard to enter digits, decimal points, and elementary functions. You can also use your backspace key (or the "backspace" button) to correct errors. To extract a number from the display to the clipboard, right-click on the display and Select All, then right-click again and Copy the number to the clipboard. The precision of the calculator can be set by changing the value in the "digits:" field. The default value is 80 digits, but you can set it to 10000 digits or whatever you want. Naturally the calculator gets more and more sluggish as the number of digits goes up. Note that this is only the number of decimal places that the calculator will generate when dividing, and when performing scientific functions like logarithms, sines, etc. Addition, subtraction, and multiplication always conserve all digits. Multiplying an 80 digit number by another 80 digit number will yield a number that has 160 digits- and many of them may not be significant. For example, if you're working with 20 digits, the square root of 5 is:  2.23606797749978969641 Multiply this number by itself (click "x" and "="), and the calculator will give you:  5.0000000000000000000036954657775999668881 The trailing digits (i.e., 36954...) are just rounding error garbage.  Click on the "roundoff" button at the top, and the number will be rounded to:  5.00000000000000000000 which is the "correct" number. The "CE/C" key works just like it does on a normal calculator (press once to clear entry, twice to clear everything). To raise a number to a power, use the "x^y" key. For example, to get 2100, click "2", "x^y", "100", "=". To take roots, use the "rootn" key. For example, to get the cube root of 8, click "8", "rootn", "3", "=". The "R-D" button switches between degrees and radians. The "break" button interrupts the calculator if it gets caught in a long calculation (like the factorial of one million). The "calculator busy" light is at top right. And if you click on my name, you'll be sending mail to the author (me). The calculator is otherwise fairly self-explanatory.