Help

Note that this help is available from within the calculator, just select Help from the main menu.

Basic Operation

Number Entry

The number keys to and decimal point are used to enter numbers. To enter a negative number, press after entering the number.

The key deletes the last digit entered and can be used to correct a number or exponent.

The key clears the display ready for a new calculation.

Exponents

To enter a number with an exponent, press then enter the exponent using the number and keys. Note that the exponent key means 'times 10 to the power' and it is not necessary to enter the 'times 10' yourself.

For example, to enter 2.5x10¹², press:

→ 2.5x10¹²

Secondary Functions

The key is used to access the secondary function of each key (displayed above the key in orange). While shift is active, 'SHIFT' will be shown on the display. Press again to cancel shift mode.

As an alternative to using shift, the secondary function of each key can also be accessed by holding down the key. This feature can be disabled in Settings.

Throughout this help, functions which require shift to access are shown in orange. The shift key itself is not shown.

Display

Number Format

Numbers can be formatted on the display using either a point or a comma as the decimal separator. Numbers can also be displayed with digit grouping, using either a comma/point or space to separate groups of digits.

In decimal mode, numbers are displayed in groups of three digits. For binary, hexadecimal or octal mode, numbers are displayed in groups of four digits. These options can be set via the Settings screen.

Display Modes

There are four display modes for calculation results. Use the key to cycle through the modes. The display will show 'FIX', 'SCI', 'ENG' or blank to indicate the current mode.

Decimal Places

To set the number of decimal places in FIX mode, or the number of significant digits in SCI or ENG modes, press . This will bring up a dialog to select the number of digits, together with the current value rounded appropriately. When the number of digits selected is less than the maximum available, the display will show the number of digits after the mode indicator e.g. FIX:5 or SCI:8.

Normal mode

The result is displayed as a normal floating point value if possible. If its magnitude is less than 0.0001 or greater than 9,999,999,999 then scientific notation is used (see SCI mode below). The number of decimal places cannot be adjusted in this mode.

FIX mode (fixed decimal point)

The result is displayed after rounding to the number of decimal places selected by . If there is not enough room, the result may be displayed with fewer decimal places.

SCI mode (scientific notation)

The result is displayed in the format A x 10^B, with the mantissa (A) rounded to the number of significant digits selected by .

ENG mode (engineering notation)

This is the same as SCI mode, except that the exponent is set to a multiple of 3.

Note

The value used for calculations is the unrounded result stored internally, and not the rounded value shown on the display.

Result History

Each time the key is pressed, the calculation result is added to a history list.

The key presents a dialog showing the calculation result history, with the most recent results at the top. Select the required value to enter it into the calculator.

History Size

The maximum number of results which are stored can be set via the Settings screen (Menu->Settings). When set to 'Off', the key simply recalls the last result, without showing a dialog.

Unique History

By default, the values in the history list are unique. If a calculation result is the same as one already in the history list, this value is moved to the top. This behaviour can be changed via the Settings screen.

History Reset

The history list can be cleared via the options menu.

Memories

Main Memory

The main memory has four dedicated function keys:

stores the current display value into the main memory.

recalls the value stored in the main memory.

adds the current display value to the main memory.

subtracts the current display value from the main memory.

Whenever a non-zero value is stored in the main memory, the letter 'M' is shown on the display.

The main memory can also be accessed via the and keys (see below).

Additional Memories

There are nine additional memories which can be accessed via the and keys. These keys show a dialog with the current values stored in the main memory 'M' and the additional memories '1' to '9'. Select the appropriate value to store or recall the memory value.

Memory Reset

The values stored in all the memories can be reset to zero via the options menu.

Unit Conversion

How to Convert

The current display value can be converted between different units using the key.

First, select the unit type from the list (distance, area, speed, time, etc).

Second, select the unit to convert from. Drag the list up/down to scroll if necessary.

The dialog will show the value converted to all appropriate units, with the original value highlighted in orange.

Select the required value to enter it into the calculator.

Press the back button at any time to go back to the previous step.

Zero Values

For most conversions, an original value of 0.0 will be replaced by 1.0 as a convenience to avoid converting zero to zero. This does not apply to conversions which are not a simple ratio, e.g. temperature.

Notes

The unit conversion dialog only displays values in decimal, the current radix mode (BIN, OCT or HEX) is ignored.

Basic Functions

Arithmetic Calculations

These are entered exactly as written:

→ 75.

Operations can be joined together:

→ 11.

Multiplication and division have precedence over addition and subtraction and will be performed first:

→ 7.

The parentheses keys can be used to override the normal precedence:

→ 9.

There is no limit to the number of parentheses which can be entered.

Percentage Calculations

What is 10% of 200?

→ 20.

What percentage of 36 is 9?

→ 25.

What is a 10% increase of 200?

→ 220.

What is a 20% decrease of 500?

→ 400.

Powers and Roots

Find 20²

→ 400.

Find 6³

→ 216.

Find the square root of 25

→ 5.

Find the cube root of 64

→ 4.

Find the 4th root of 81

→ 3.

Reciprocals

Find 1/4 + 1/5

→ 0.45

Constants

Find 2 pi

→ 6.283185307

Find 1 / e

→ 0.367879441

Modulo

The modulo function calculates the remainder after division. Integer and non-integer numbers are supported. For negative numbers, the result has the same sign as the divisor.

Find remainder after dividing 25 by 7

→ 4.

Find remainder after dividing 8.5 by 2.6

→ 0.7

Find -8 modulo 5

→ 2.

Find 8 modulo -5

→ -2.

Repeat Calculations

Repeat calculations can be performed without re-entering the value and function key, for example:

→ 30.

20 is now a constant for addition:

→ 80.

→ 50.

→ 70.

→ 90.

Similarly for subtraction, multiplication and division:

→ 7.

→ 12.

→ 4.

→ 10.

→ 14.

→ 25.

→ 20.

Advanced Functions

Logarithms and Exponentiation

Find ln(20.1)

→ 3.000719815

Find log(316)

→ 2.499687083

Find e³

→ 20.08553692

Find 10^2.5

→ 316.227766

Trigonometric Functions

For trigonometric functions, angles can be specified in degrees, radians or grads. The key cycles through the angle modes, and the display will show DEG, RAD or GRAD to indicate the current mode.

The key also cycles through the angle modes, but also converts the current value in the display.

Find sin(30) (in DEG mode)

→ 0.5

Find tan(pi/4) (in RAD mode)

→ 1.

Find arcos(0.5) (in DEG mode)

→ 60.

Convert 180 degrees to radians

→ 3.141592654

Hyperbolic Functions

For hyperbolic functions press the key before pressing , or . For inverse hyperbolic functions use in combination with . The 'HYP' indicator will appear in the display.

Find sinh(4)

→ 27.2899172

Find arcosh(9)

→ 2.88727095

Factorials and Permutations

Find 10!

→ 3,628,800.

Find permutations of 3 items from 5

→ 60.

Find combinations of 3 items from 5

→ 10.

Fractions & DMS

Note

Please note that Fractions and DMS are only available in RealCalc Plus.

Fractions

Fractions are entered using the key, and can be entered as either mixed or improper fractions. The results of calculations involving fractions will be displayed as fractions where appropriate, reduced to their lowest terms.

Fraction Calculations

Find ²/₃ + ³/₄

→ 1⁵/12

Find ¹¹/₈ - 2¹/₂

→ -1¹/8

Find 1³/₈ x ³/₂

→ 2¹/16

Fraction Conversion

The key also converts between mixed fraction, improper fraction and decimal format.

Convert 3/8 to decimal, then back to fraction

→ 0.375

→ ³/8

Convert 2.55 to fraction, then to improper fraction, then to decimal

→ 2¹¹/20

→ ⁵¹/20

→ 2.55

If a decimal value cannot be converted to a fraction, then the

key does nothing

→ 3.141592654

Limits

The following restrictions apply to fraction entry and results:

The maximum supported denominator is 99999.

The maximum number of digits in mixed fraction format is 10.

Calculation results which do not meet these restrictions will be converted to decimal.

Degrees, Minutes and Seconds (DMS)

DMS values are entered using the key, and can be entered as either decimal degrees, whole degrees with decimal minutes, or whole degrees and minutes with decimal seconds.

DMS Calculations

Find 2�30' + 1�45'20"

→ 4�15'20.00"

Find 2�3.5' + 125.3'

→ 4�08'48.00"

DMS Conversion

The key also converts between DMS and decimal format.

Convert 1.25 to DMS, then back to decimal.

→ 1�15'00.00"

→ 1.25

Convert 2�30 to decimal, then back to DMS.

→ 2.5

→ 2�30'00.00"

Limits

The maximum value which can be displayed as DMS is 9999�59'59.99". Calculation results outside this range will be converted to decimal.

Binary, Octal and Hex

Changing Mode

These modes are set using the , and keys respectively. The key returns to the normal decimal mode. The current value on the display is converted when switching modes.

Please note that these modes are disabled by default, and can be enabled in the settings.

Number Range

When in BIN, OCT or HEX modes, calculations are performed on signed integer values up to 12 digits. Non-integer results will be truncated.

Negative values are represented in 2's, 8's or 16's complement notation.

Example:

→ -1.

→ 1111,1111,1111.

→ 7777,7777,7777.

→ FFFF,FFFF,FFFF.

Pressing the key negates the current value on the display:

→ 1111,1111,1001.

→ 111.

Logical Operations

In BIN, OCT or HEX modes, additional logical operation keys become available:

- bitwise inversion

- bitwise logical AND

- bitwise logical NAND

- bitwise logical OR

- bitwise logical NOR

- bitwise exclusive-OR

- bitwise exclusive-NOR

History and Memory Dialogs

When in BIN, OCT or HEX modes, the values in the history and memory dialogs are presented in the current mode. Values which cannot be converted to the current mode are shown as 'Error' and cannot be selected.

RPN Mode

RPN Operation

RPN mode can be enabled via the Settings screen.

In this mode, values are entered first, followed by the function key. Values are pushed onto a stack using the key. Functions take their arguments off the bottom of the stack, and push their result back onto the stack. The depth of the stack is unlimited.

Functions which require a single argument, such as or , simply operate on X and replace it, in the same way as normal mode:

→ X: 25.

Functions which require two arguments, such as or , take X and Y off the stack and put the result back:

→ X: 6.

→ X: 256.

If the stack is empty, i.e. there is no value in the Y register, 'Y?' will be displayed for a short time when trying to do an operation which requires two arguments.

Find (4+5)/(1+2)

→ X: 3.

Note that as all operations are immediate, there is no need for parentheses or an equals key.

Stack Operations

The following additional functions are available in RPN mode:

The

key drops the X value off the bottom of the stack, shifting the remainder of the stack down.

The

key swaps the values in the X and Y registers.

The

key restores the value which was in the X register before the last operation.

The

key opens a dialog which shows the contents of the stack.

Display

The display shows the current value at the bottom of the stack, X, and the next value, Y. This can be changed in the settings to show just the X register, or X, Y and Z. The size of the calculator keys is reduced compared to normal mode when showing X/Y or X/Y/Z.