Calc is a pocket calculator simulator program for the Microsoft Windows operating systems, including handheld devices using Windows CE, such as Pocket PC. It can be used in place of the calculator program which is included with the operating system, with many additional features and greater flexibility. On handheld devices, it can be carried around instead of a pocket calculator. It is especially designed for scientific and engineering students and professionals and includes a wide range of units conversions and scientific functions. It also has statistics, financial and time functions, including a stopwatch.

Despite the range of features, Calc98 is very compact in terms of screen
space, so you can keep it maximized while working within another application and
make use of the 'always on top' option, or keep it in the system tray. You can
also customize the appearance of Calc98, including the resizing of buttons and
their fonts and layout. Just as with a conventional calculator, space is at a
premium, so many of the calculator buttons have to double up the functions they
provide. The layout of the calculator in its normal state has the functions you
would expect to see on a fairly standard scientific calculator, which means that
it is probably self explanatory. But pay special attention to the `shift`
button in the top left hand corner, because this allows you to access additional
functions which are not normally visible on the keypads. The buttons change when
you press the `shift`
button. If you press the `shift` button again, the buttons revert to
their un-shifted state.

You can enter numbers either by clicking on the buttons with a mouse or
stylus, or using the keyboard. You can use the numeric keypad to enter numbers
and simple arithmetic operators (make sure Num Lock is on). The enter key can be
used as an additional equals key (except in RPN mode).
Most of the calculator functions can be accessed from your computer keyboard
(these are sometimes called 'keyboard shortcuts' or 'keyboard accelerators').
Keyboard accelerators are listed by key and by
meaning. You can also use the Caps Lock key on your keyboard instead of the `
shift` button.

The menu bar (or command bar) can be used to give access to additional functions.

Clears the calculator, and resets any functions. The contents of the
memory are not affected by `AC`. The memory can be cleared after
pressing
`AC`
by pressing `Min`.

Erases the last number or operation entered.

This button performs addition.

This button performs subtraction.

This button performs division.

This button performs multiplication.

Displays the result of an arithmetic operation. It can be used during a
calculation to ensure that an intermediate result has been evaluated. Unless the `
= ` button is pressed, it is possible that an operation is incomplete -
pressing ` = ` ensures that no arithmetic operations are pending.

Certain functions make use of the ` = ` button to signify the end of
input, in order to evaluate a result.

This button (`shift` ` = `
or Enter button) displays the result of an arithmetic operation as a percentage.

Examples:

Calculate five sixteenths as a percentage.

**5 / 1 6 shift % **

Result: 31.25%

Calculate 17.5% of � 250.00:
**250 x 17.5 shift % **

Result: � 43.75

Calculate 12% mark-up on $250
**250 + 12 shift % **

Result: $280

Give 5% discount on goods costing $125
**125 - 5 shift % **

Result: $118.75

This button (shifted Exp button) displays the value of pi (the ratio of the circumference of a circle to its diameter).

Pressing this button adds the number displayed to the contents of the memory.
Additional memories can be accessed by pressing the `shift` key before
pressing this button, which will change to `Mn+`.

Add to one of ten memories (labelled 0-9) using this button, which is
obtained by pressing the `shift` button. After pressing `Mn+`
press the number button corresponding to the desired memory. Memory number zero
is the default memory (i.e. the memory referred to by the un-shifted memory
buttons).

Press the `min` button to enter the currently displayed number into
the memory.

If you first press `shift` before `Min` you can select one
of the ten memories (0-9). Memory zero is the default memory, i.e. the memory
available without pressing the `shift` button.

Input a value to one of ten memories (labelled 0-9) using this button, which
is obtained by pressing the `shift` button. After pressing `MnIn`
press the number button corresponding to the desired memory. Memory number zero
is the default memory (i.e. the memory referred to by the un-shifted memory
buttons). The "Clear All" button allows you to delete the contents of all the
memories.

Use this button to put the contents of the memory onto the display. The
default memory is number zero. To display other memories, first press the
`shift` button and then the `MR` button and select the
required memory.

Access one of ten memories (labelled 0-9) using the this button, which is
obtained by pressing the `shift` button. After pressing `MnR`
press the number button corresponding to the desired memory. Memory number zero
is the default memory (i.e. the memory referred to by the un-shifted memory
buttons).

Use the ` . ` button to enter the decimal part of a number. The
decimal point is disabled in non-decimal number systems.

Use this button to enter a number in exponent form. To input a number, enter
the mantissa, followed by the `EXP` key, then `+/-` if
required, then the exponent. To enter a negative number, use the `+/-`
before the `EXP` key.

Example:

To enter the number 1.234 x 10^6 (1.234E6) press the following buttons:

**1 . 2 3 4 EXP 6**

Number buttons are used in all modes. In
Hexadecimal mode they are augmented by the letters A to F. In Octal mode the 8
and 9 buttons are disabled. In Binary mode only the numbers 0 and 1 are enabled.
In *statistics mode*
the number buttons are used with the `shift` button to obtain the
statistical functions.

Use the shift button to access additional functions. The functions available depend on the calculator mode, and are indicated by changes to the legends on the calculator buttons.

If you get an error, the calculator display will contain an appropriate
message, and possibly some further descriptive information. In the case of
certain errors, the calculator functions are disabled and you need to press the `
AC` button to clear the error.