SR-281 / SR-282

Scientific Calculator

General Guide.................................................................................... 2

Turning on or off ..............................................................................2

Battery replacement.........................................................................2

Auto power-off function.................................................................... 2

Reset operation ...............................................................................2

Contrast adjustment.........................................................................3

Display readout................................................................................ 3

Before Starting Calculation.............................................................. 4

Using " MODE " keys....................................................................... 4

Using " 2nd " Keys........................................................................... 4

Corrections ......................................................................................4

Undo function ..................................................................................4

Replay function................................................................................ 5

Memory calculation.......................................................................... 5

Order of operations.......................................................................... 6

Accuracy and Capacity.................................................................... 7

Error conditions ...............................................................................9

Basic Calculations ............................................................................9

Arithmetic calculation..................................................................... 10

Parentheses calculations............................................................... 10

Percentage calculation ..................................................................11

Display notations ........................................................................... 11

Scientific Functional Calculations................................................. 13

Logarithms and Antilogarithms ...................................................... 13

Fraction calculation ....................................................................... 13

Angle unit conversions ..................................................................14

Sexagesimal ↔ Decimal transformation........................................15

Trigonometric / Inverse-Tri. functions ............................................ 15

Hyperbolic / Inverse-Hyp. functions............................................... 16

Coordinates transformation ...........................................................16

Probability...................................................................................... 17

Other functions ( 1/x, ,3,X, x 2, x 3, x y , INT, FRAC ) ........ 18

Unit Conversion ............................................................................. 19

Physics constants.......................................................................... 19

Base–n calculations........................................................................ 24

Bases conversions ........................................................................25

Block Function ............................................................................... 25

Basic arithmetic operations for bases............................................ 27

Negative expressions ....................................................................27

Logical operation ...........................................................................27

Statistical Calculations................................................................... 27

Entering data .................................................................................28

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Displaying results ..........................................................................28

Deleting data .................................................................................31

Editing data.................................................................................... 32

FULL message...............................................................................32

Complex Calculations..................................................................... 33

General Guide

Turning on or off

To turn the calculator on, press [ ON/C ] ; To turn the calculator off,
press [ 2nd ] [ OFF ].

Battery replacement

SR-281 is powered by two alkaline batteries (GP76A or LR44).

SR-282 is powered two AA-size ( UM-3 ) batteries. If the display

becomes dim and difficult to read, the batteries should be replaced as
soon as possible.

To replace batteries :

1) Slide the battery compartment cover in the direction indicated by
the arrow and remove it.

2) Remove the old batteries and install new ones with polarity in
correct directions, then replace the battery compartment cover
and press [ ON/C ].

Auto power-off function

This calculator automatically turns it off when not operated for
approximately 6~9 minutes. It can be reactivated by pressing [ ON/C ]
key and the display, memory, settings are retained.

Reset operation

If the calculator is on but you get unexpected results, press [ MODE ]
[ 4 ] ( RESET ) in sequence. A message appears on the display to
confirm whether you want to reset the calculator and clear memory
contents.

RESET : N Y

Move the cursor to " Y " by [ ], then press [ ] to clear all
variables, pending operations, statistical data, answers, all previous
entries, and memory; To cancel the reset operation without clearing
the calculator, please choose " N ".

If the calculator is lock and further key operations becomes impossible,
please press [ 0 ] [ CE ] at the same time to release the condition. It will
return all settings to default settings.

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Contrast adjustment

Pressing the [ – ] or [ + ] following [ MODE ] key can make the contrast
of the screen lighter or darker. Holding either key down will make the
display become respectively lighter or darker.

Display readout

The display comprises two lines and indicators. The upper line i s a dot
display up to 128 characters. The lower line is capable of displaying a
result of up to 12 digits, as well as 2-digits positive or negative
exponent.

When formulas are input and executed the calculation by [ ],
they are displayed on the upper line, and then results are shown on
the lower line.

The following indictors appear on the display to indicate you the
current status of the calculator.

Indicator Meaning

M Running memory
– Result is negative
E Error
STO Storing variable mode is active
RCL Recall ing variable mode is active
2nd 2nd set of function keys are active
HYP Hyperbolic-trig function will be calculated
ENG Engineering symbol notation
CPLX Complex number mode is active
CONST Display physics constants
DEGRAD Angle mode : DEGrees, GRADs, or RADs
BIN Binary base
OCT Octal base
HEX Hexadecimal base
( ) Open parentheses
TAB Number of decimal places displayed is fixed
STAT Statistics mode is active
REG Regression mode is active
EDIT Statistics data is being edited
CPK CPK : Process capability
CP : Precision capability
USL Set upper specification limit
LSL Setting lower specification limit
i Imaginary part

Allow to use undo function

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Before Starting Calculation

Using " MODE " keys

Press [ MODE ] to display mode menus when specifying an operating
mode ( " 1 MAIN ", " 2 STAT ", " 3 CPLX ", " 4 RESET " ) or the
engineering symbol notation ( " 5 ENG " ).

1 MAIN : Use this mode for basic calculations, including scientific

calculations and Base–n calculations.

2 STAT : Use this mode to perform single–variable and

paired–variable statistical calculati ons and regression
calculations.

3 CPLX : Use this mode to perform complex number calculation.

4 RESET : Use this mode to perform reset operation.

5 ENG : Use this mode to allow engineering calculations utilizing

engineering symbol.

Give " 2 STAT " as an example :

Method 1 : Press [ MODE ] and then scroll through the menus using

[ ] or [ 2nd ] [ ] until " 2 STAT " is underlined,
then enter the desired mode by pressing [ ].

Method 2 : Press [ MODE ] and then key in directly the number of the

mode, [ 2 ] , to enter the desired mode immediately.

Using " 2nd " Keys

When you press [ 2nd ], the " 2nd " indicator shown in the display is to
tell you that you will be selecting the second function of the next key
you press. If you press [ 2nd ] by mistake, simply press [ 2nd ] agai n to
remove the " 2nd " indicator.

Corrections

If you have made a mistake when entering a number (but you have not
yet pressed an arithmetic operator key), just press [ CE ] to clear the
last entry then input it again, or delete individual digits by the
backspace key [ ], or cl ear all entry by [ ON/C ].

After making corrections, input of the formula is complete, the answer
can be obtained by pressing [ ]. You can also press [ ON/C ] to
clear the immediate results completely (except clearing memory). If
you press the wrong arithmetic operation key, just press the correct
key to replace it.

Undo function

The unit offers an undo function which allows you to undo some of the
errors you just have made.

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When a character which is just deleted by [ ], an entry which is just
cleared [ CE ], or which is just cleared by [ ON/C ], the " " indicator
shown in the display is to tell you that you can press [ 2nd ] [ ] to
cancel the operation.

Replay function

This function stores operations that just have been executed. After
execution is completed, pressing [ ] or [ 2nd ] [ ] key will
display the operation executed. Pressing [ ] will display the
operation from the beginning, with the cursor located under the first
character. Pressing [ 2nd ] [ ] will display the operation from the
end, with the cursor located at the space following the last character.
You can continue moving the cursor by [ ] or [ 2nd ] [ ] and
editing values or commands for subsequent execution.

Memory calculation

Memory variable

The calculator has nine memory variables for repeated use -- A, B, C,
D, E, F, M, X, Y. You can store a real number in any of the nine
memory variables.

• [ STO ] + [ A ] ~ [ F ], [ M ], [ X ] ~ [ Y ] lets you store values to
variables.

• [ RCL ] + [ A ] ~ [ F ], [ M ], [ X ] ~ [ Y ] recalls the value of the
variable.

• [ 0 ] [ STO ] + [ A ] ~ [ F ], [ M ], [ X ] ~ [ Y ] clears the content to a
specified memory variable.

(1) Put the value 30 into variable A

¾

30 [ STO ] [ A ]

(2) Multiple 5 to variable A, then put the result into variable B

¾

5 [ x ] [ RCL ] [ A ] [ ]

[ STO ] [ B ]

(3) Clear the value of variable B

¾

0 [ STO ] [ B ]

DEG

30Æ A

30.

DEG

5 ¼A=

150.

DEG

150Æ B

150.

DEG

0 ÆB

0 .

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[ RCL ] [ B ] [ ]

DEG

B=

0 .

Running memory

You should keep the following rules in mind when using running
memory.

• Press [ M+ ] to add a result to running memory and the " M " indicator

appears when a number is stored in the memory. Press [ MR ] to
recall the content of running memory.

• Recalling from running memory by pressing [ MR ] key does not

affect its contents .

• Running memory is not available when you are in statistics mode.

• The memory variable M and running memory utilize the same

memory area.

• In order to replace the content of the memory with the displayed

number, please press [ X M ] key.

• To clear the content of running memory, you can press [ 0 ] [ X M ],

[ CE ] [ X M ] or [ 0 ] [ STO ] [ M ] in sequence.

[ ( 3 x 5 ) + ( 56 7 ) + ( 74 – 8 x 7 ) ] = 41

¾

0 [ X M ]

3 [ x ] 5 [ M+ ] 56 [ ] 7 [ M+ ] 74
[ – ] 8 [ x ] 7 [ M+ ]

[ MR ]

0 [ X M ]

(Note) : Besides pressing [ STO ] or [ X M ] key to store a value, you

can also assign values to memory variable M by [ M+ ].
However, when [ STO ] [ M ] or [ X M ] is used, previous
memory contents stored in variable M are cleared and
replaced it with the newly assigned value. When [ M+ ] is used,
values is added to present sum in memory.

DEG

DEG

74–8¼ 7M+

M

DEG

M

M

DEG

0 .

18.

41.

0 .

Order of operations

Each calculation is performed in the following order of precedence:

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1) Fractions

2) Expression inside parentheses.

3) Coordinates transformation ( P R , R P )

4) Type A functions which are required entering values before
pressing the function key, for example, x2,1/x, Ӹ, x!, %, RND,
ENG, , , x ', y ' .

X

5) x y,

6) Type B functions which are required pressing the function key
before entering, for example, sin, cos, tan, sin –1, cos –1, tan –1,
sinh, cosh, tanh, sinh –1, cosh –1, tanh –1, log, ln, FRAC, INT, Ѕ,

3

, 10 X , e X, NOT, EXP, DATA in STAT mode.

7) + / –, NEG

8) nPr, nCr

9) x ,

10) +, –

11) AND, NAND –-- only Base–n mode

12) OR, XOR, XNOR --- only Base–n mode

Accuracy and Capacity

Output digits : Up to 12 digits.

Calculating digits : Up to 14 digits

In general, every reasonable calculation is displayed up to 12 digits
mantissa, or 12-digits mantissa plus 2-digits exponent up to 10

Numbers used as input must be within the range of the given function
as follow :

Functions
sin x
cos x
tan x

Deg :

Rad :

Grad :

x <

x <

x <

Input range

4.5 x 10 10deg

8

Ӹ

2.5 x 10

10

5 x 10

grad

rad

however, for tan x

Deg :

Rad :

Grad :

sin –1x, cos –1x x

tan –1x

sinh x, cosh x

x <

x

90 (2n+1)

x ≠

π

(2n+1)

x ≠

2

100 (2n+1), (n is an integer)

x ≠

1

싪

100

1 x 10

230.2585092

싪

± 99

.

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tanh x

sinh –1x

cosh–1x

tanh –1x

log x, l n x

x

10

x

e

x

2

x

3

x

1/x

3

x

X !

R P

P R

y

x

x

y

x <

x <

1

싪 x < 5 x 10

x <

1 x 10

–1 x 10

–1 x 10

싪

0

x <

x <

x <

x <

싪

0

싪

0

Deg

Rad

Grad

99

5 x 10

99

1

–99

싪

x < 1 x 10

100

< x < 100

100

< x 싪 230.2585092

x < 1 x 10

1 x 10

100

100

50

2.15443469003 x 10

100

1 x 10

, x ≠ 0

100

1 x 10

x 싪 69, x is an integer.

y+x

r< 1 x 10

Κ

ཎθཎ<

Κ

ཎθཎ<

Κ

22

1 x 10

<

100

4.5 x 10 10 deg

2.5 x 10

5 x 10 10 grad

ཎθཎ<

100

8

Ӹ

rad

33

100

1 x 10

however, for tan x

Κ

Deg

Rad

Grad

90 (2n+1)

ཎθཎ≠

π

Κཎθཎ≠

Κ

ཎDཎ, M, S < 1 x 10

x <

x > 0 : –1 x 10

x = 0 : y

x

< 0 : y = n, 1/(2n+1), n is an integer.

but –1 x 10

y> 0 : x ≠ 0, –1 x 10

y = 0 : x

< 0 : x=2n+1, l/n, n is an integer.(n≠0)

y

(2n+1)

2

100 (2n+1), (n is an integer)

ཎθཎ≠

1 x 10

100

, 0 싪 M, S

100

100

< y log x < 100

> 0

100

< y log ཎxཎ < 100

1

100

<

x

> 0

log y < 100

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1

100

ab/c

nPr, nCr

STAT

DEC

BIN

but –1 x 10

Input

ΚTotal of integer, numerator and

denominator must be within 12 digits
(includes division marks)

Result

ΚResult displayed as fraction for

integer when integer, numerator and
denominator are less than 1 x 10

싪

0

r 싪 n, n 싪10

x

1 x 10 50 ,

<

Ӻx,Ӻ

y,x,y,a, b, r : n ≠ 0 ;

Κ

n≠ 0, 1 ; x n = 50 ; y n = 50 ;

Sx, Sy
Number of repeats 255, n is an integer.

– 2147483648

싪

0싪 X

01111111111111111111111111111111

log ཎyཎ< 100

<

x

100

, n,r are integers.

y

1 x 10

<

싪

X 싪 2147483647

12

50

(for zero or positive)

10000000000000000000000000000000

싪

X싪11111111111111111111111111111111

(for negative)

OCT

싪

0

X 싪 17777777777 (for zero or positive)

20000000000

싪

X 싪 37777777777

(for negative)

HEX

싪

0

X 싪 7FFFFFFF ( for zero or positive)

싪

80000000

X싪 FFFFFFFF (for negative)

Error conditions

Error message “ E ” will appear on the display and further calculation
becomes impossible when any of the following condition occur.

1) You attempted to divide by 0

2) When allowable input range of function calculations exceeds the
range specified

3) When result of function calculati ons exceeds the range specified

4) When the [ ( ] key is used more than 13 levels in a single
expression

5) When USL

LSL value

<

To release the above errors, please press [ ON/C ].

Basic Calculations

Use MAIN ( [ MODE ] 1 ( MAIN ) ) mode for basic calculations.

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Arithmetic calculation

Arithmetic operations are performed by pressing the keys in the same
sequence as in the expression.

7 + 5 x 4 = 27

¾

7 [ + ] 5 [ x ] 4 [ ]

DEG

7+5¼4=

27.

For negative values, press [ +/– ] after entering the value; You can
enter a number in mantissa and exponent form by [ EXP ] key.

¾

Results greater than 10 12 or less than 10

– 5

2.75 x 10

2.75 [ EXP ] 5 [ +/– ] [ ]

= 0.0000275

DEG

2 . 75E–05=

0. 000 02 75

–11

are displayed in

exponential form.

12369 x 7532 x 74103 = 6903680612720

¾

= 6.90368061272 x 10

12369 [ x ] 7532 [ x ] 74103
[

]

12

DEG

12369¼ 7532¼ 7

6. 90368061272

12

Parentheses calculations

Operations inside parentheses are always executed first. SR-281 /

SR-282 can use up to 13 levels of consecutive parentheses in a single

calculation.

Closed parentheses occurring immediately before operation of the [ ) ]
key may be omitted, no matter how many are required.

2 x { 7 + 6 x ( 5 + 4 ) } = 122

¾

2 [ ( ] 7 [ + ] 6 [ ( ] 5 [ + ] 4 [ ]

(Note) : A multiplication sign " x " occurring immediately before an

open parenthesis can be omitted.

The correct result cannot be derived by entering [ ( ] 2 [ + ] 3 [ ) ] [ EXP ]

2. Be sure to enter [ x ] between the [ ) ] and [ EXP ] in the below

example.

DEG

2 ¼ (7+6¼ (5+4=

122.

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