Stokes Publishing MathMaster Reference Manual

Reference Manual for the

MathMaster

™

Educational Calculator

a product of

Stokes Publishing Company

Sunnyvale, CA

MathMaster

®

K E Y E L I M I N A T O R

2

0

•

3

1

5

8

6

x

–

M+

+/–

%

MRC

RESET

4

7

+

=

CE

/

C

M

–

÷

9

8

M+

MRC

RESET

4

7

MathMaster Key List

c Clear entry, clear
0-9, . Numeric input
+-x/

Operations

= Result
M Add to memory

m Subtract from memory
r Memory recall, memory clear
$

RESET

Clears decimal fix and

all pending operations

_

Toggles sign of dispayed number

% Percent
v Square root

MathMaster is a registered trademark of Stokes Publishing Company
Key Eliminator is a trademark of Stokes Publishing Company
©1995 Stokes Publishing Company • Sunnyvale, California

3

Welcome to the exciting world of the

MathMaster calculator. You will be using
the “world’s finest four-function calculator,”
the only one with the patented feature, the
Key Eliminator. To take full advantage of
the many features and functions of the
MathMaster, go through this manual with
MathMaster in hand following the explana­tory sequences. Most sequences contain
single-digit numbers so you can concentrate
on the process rather then on cumbersome
computations. You will then gain the
confidence and know-how to use the
MathMaster to perform difficult computa­tions with speed and accuracy.

Exciting Features of the MathMaster

• Eliminator

This new, patented function will allow
the user to disable or make inactive one
or more keys.

• Constants

The MathMaster has full constant capabili­ty for all four operations. A counter show­ing in the display indicates the number of
times the constant has been used.

4

• Fixing the Number of Decimal Places

The decimal point may be fixed to a desig­nated number of places, from 0 to 7.

• RESET

Pressing the RESET key will reactivate any
keys that have been disabled and return
the calculator to floating decimal point
notation. All constants, pending opera­tions, and contents of memory will be
cleared.

• Operation Icons

Icons for the operations of addition,
subtraction, multiplication, and division
will appear on the right side of the display
in a large five-by-five dot matrix to indicate
what operation is being processed or is
pending.

• Logic System

All operations are processed according to
the standard algebraic order of operations
(MDAS).

• Reading Large Numbers

Large numbers in the display are easy to
read. The periods of a large number are
separated with an apostrophe at the top
of the number.

5

Guide to Display Symbols

The display holds up to eight digits. In addi­tion, there are indicators which will appear
in the display to alert you to the status of the
various features and functions of the
MathMaster.

Indicator Description Page

’

Separates large numbers
into periods 4

+

Operation of addition in
progress or pending 4

–

Operation of subtraction in
progress or pending 4

x

Operation of multiplication in
progress or pending 4

÷

Operation of division in
progress or pending 4

E

Calculation resulted in error; or

(error)

display or memory exceeded 7

M

Non-zero number is stored in
memory 10

FIX

The number of decimal places
is fixed at 0 to 7 places. 14

•

Eliminator feature is in effect. 15

6

Key Functions

c, Digit keys and =

Press c to turn on the calculator. You

should have a “0” in the display.
To display 12, press

12.

Clear the display by pressing

c.

To display 21, press

21.

Clear the display by pressing

c.

To display 3’287’914, press

3287914. Note the apostro-

phes at the top of the display separate this
seven-digit number into periods of three for
ease of reading.
Clear the display by pressing

c.

Press

5+3=. Display 8. Notice that

when the addition key was pressed, the
addition icon appeared on the right side of
the display.

Press

9-2=. Display 7. Notice that it

was not necessary to clear the display. If the

= key is pressed between separate calcula-

tions, you do not have to clear the display.
Use

c to clear a numerical input error.

Press

6+7 ‘Erase” the 7 by pressing

c4=. Display 10 (6 + 4).

7

Press c to clear the current number in

display.
Press

6+7cc. Display 0.

The addition calculation has been cleared,
as well as both arguments.

Press c to clear errors. Key in

99,999,999.
Press

+1=. The display shows the error

indicator. The sum exceeds the display’s 8-
digit capacity. Press

c. Display 0. The

error has been cleared.

Round Off

The MathMaster performs precise calcula­tions with a round-off feature. Press

2/3=. The right-most digit is a 7. The

rounded-off decimal equivalent for 2/3 is dis­played. Press

x9=. Display 6 (2/3 x 9).

Logic System

All operations are processed according to
the standard algebraic order of operations.
For 2 x 3 + 5, press

2x3+5=.

Display 11.
For 5 + 2 x 3, press

5+2x3=.

Display 11.

8

For 4 x 5 + 3 x 2, press

4x5+3x2=. Display 26.

For 4 x (5 + 3 x 2), press

5+3x2=x4=. Display 44.

Constant Operations

Use the constant feature to repeatedly
operate with the same number.

Example Press Display

Use 4 as a constant. RESET or CE/C 0
2 + 4, 5 + 4,
7 + 4, 9 + 4 2 2

+ 2 [+]
44

2 + 4 = 6

5 5 [+]

5 + 4 = 9

7 7 [+]

7 + 4 = 11

9 9 [+]

9 + 4 = 13

9

Example Press Display

RESET or CE/C 0

10 x = = = = = 10 10

x 10 [x]
10 x10 = 100
10 x 10 x10 = 1000
10 x10 x10 x10 = 10000
10 x10 x10 x10 x10 = 100000

Notice that the counter shows the number of
times the entered number is used as a

factor.

Example Press Display

RESET or CE/C

2 + 3 = = = = = 2 2

+ 2 [+]

33
2 + 3 = 5
2 + 3 + 3 = 8
2 + 3 + 3 + 3 = 11
2 + 3 + 3 + 3 + 3 = 14

Notice that the counter, starting at 2, indi­cates the number of times the constant (3) is
being used as a addend.

Counter

Counter

2
3
4
5

2
3
4

10

Memory Keys

The three memory keys allow the user to
store, add to, subtract from, recall, and
clear numbers in memory.

M+ Adds displayed number to memory.

(memory indicator active)

M– Subtracts displayed number from

memory. (memory indicator active)

MRC Pressed once, recalls memory to dis-

play. (memory indicator active)
Pressed twice, clears memory. (mem­ory indicator not displayed)

Press

4+5= Display 9.

Press

M. The displayed number is stored

in memory.
The display now has an “M” in the left-hand

corner of the display. This indicator tells the
user that a non-zero number is stored.

Press

c. Display 0. The memory indica-

tor is still present.

Press r. Display 9.

Press

r. Display 9. The “M” symbol

disappears.

Press 4MMMr. Display 12.

11

Press

rr2x3=M4x5=
Mr

. Display 26

Press

rr3x7=M2x8=
mr

. Display 5

Percent Key

Press 25%. Display 0.25

(assumes 25% of 1)
To find 25% of 60, press

25%x60=. Display 15

To find 60 multiplied by 25%, press

60x25%=. Display 15

Discount and Markup

An item that sells for $80 is discounted 25%.
What is the sale price?

Press Display

80 80

– 80 [–]

25 25

%20
=60

The sale price is $60.

12

A dress costing $120 is to be marked up an
additional 20%. What will be the new price?

Press Display

120 120

+ 120 [+]

20 20

%24
= 144

The new price for the dress is $144.

A VCR selling for $250 is to be discounted
40%. What will the VCR cost including a 6%
sales tax?

Press Display

250 250

– 250 [–]

40 40

% 100
= 150
+ 150 [+]
66
%9
= 159

The total cost of the VCR, including tax is
$159.

13

Mr. Palko made a 15% commission on April
sales of $12,500 and 24% commission on
June sales of $9,250. What was the total of
his two-month commissions?

Press Display

12500 12500

x 12500 [x]

15 15

% 0.15

= 1875
M+ 1875 [M]
9250 9250

Press Display

x 9250 [x]
24 24
% 0.24
= 2220

M+ 2220 [M]
MR 4095

Mr. Palko’s total two-month commission was
$4095.

14

Change Sign Key

This key finds the opposite or additive
inverse of the displayed number.
To display the opposite of 5, press

5–.

Display -5.
To display the opposite of 237, press

237–. Display -237.

To display the opposite of 19, press

19–. Display -19.

Notice that the negative sign floats depend­ing on the number of digits.

Square Root Key

To find the square root of 49, press

49v. Display 7

To find the square root of 12.25, press

12.25v. Display 3.5

Press

x=. Display 12.25

Fixing the Number of
Decimal Places

To change from a floating decimal mode to
a designated number of places, hold down
the decimal point key for three seconds. A
range, 0-7, and the

FIX icon appears in the

display. Press 2 for two-decimal place mode;

15

0.00 will be displayed. Use a two-place
mode when working with money. If 8 or 9
is entered following the 3-second interval,
the display will return to the floating-decimal
point mode. Pressing RESET also returns the
display to the floating-decimal point mode.

Key Eliminator

This new, patented feature allows the user
to disable one or more keys by holding
down one key at a time for a period of 3-4
seconds. The user will then be unable to use
the number or operation that was eliminat­ed. A large black dot will appear in the left­hand portion of the display indicating that
this feature has been activated. When RESET
is pressed, all disabled keys are once again
active. The folllowing keys cannot be dis­abled:

c,$MR ,M,m,=, and

.. This feature provides opportunities for

the user to explore mathematics. Here is an
example: Hold down the

v

key for 3-4
seconds. You have now disabled this key.
Use a “guess and check” method to find the
square root of 28 correct to two decimal
places.

16

Notes on Percentages

A percentage must always relate to a frac­tional part of something. A statement like
“25%” is meaningless unless it is known
what the whole is. 25% of 40 is 10. 25% of
1,000 is 250, etc.

In the MathMaster, the percent key operates
in two ways, depending upon whether its
use follows an add or subtract operation, or
a multiply or divide operation. It is important
to understand this distinction when using
this calculator (or any other calculator,
for that matter, since different calculators
process percentages in different ways).

In add-on and discount problems, the calcu­lator always assumes the first number
entered as the whole, of which it finds the
requested percentage. It then displays that
fractional part and uses it as the second
number which is then either added to or
subtracted from the first number (depending
on whether it follows an add or subtract
operation) when the equals key is pressed.
When % is used following a multiply or
divide operation, the MathMaster assumes
the whole to be 1; therefore pressing 16%

17

will result in a display of 0.16. In the problem
of 40 x 16%, the first number, 40, is multi­plied by the second number, 0.16 (16% of

1) to arrive at a result of 6.4, which is consis­tent with the idea of “16% of 40.”

When none of the operations (+, –, x,

÷) are

pending, and % is used following a number
entry, MathMaster assumes that percentage
of 1. For example, if the problem sequence,
24% + 3, is keyed into the calculator, the
result will be 3.24 when the equals key is
pressed.

Changing the Calculator
Identification Numbers

The MathMaster’s unique identification sys-
tem consists of two number wheels back-to­back inside the back case; one transparent
wheel and one opaque wheel. Identification
(ID) numbers may be set from 00 to 99. Sets
of calculators are shipped with preset ID
numbers from 1 to 30 in order to relieve the
teacher of the task of setting them. However,
if you purchase fewer than 30 calculators,
you may receive some with duplicate ID
numbers, or some that duplicate the ID

18

numbers of your existing MathMasters.
To set or change ID numbers, you must
open the calculator and rotate the number
wheels so that the desired digits are visible
throught the ID window. A small philips
screwdriver is required. Read each step all
the way through before accomplishing it.

1. With the MathMaster face down, remove

the four screws securing the back case.

2. Remove the back case by lifting and rotat-

ing it to the left, and placing it back-side
down next to the main case (see figure A).

Opaque
wheel

FIGURE A

Transparent
wheel

X-shaped retainer

Retainer screw

Front of case

ID window

Lift & rotate
back of case

gently to left

Be careful not

to pull on the

battery wires

when case is

opened.

19

Note: Be careful not to break the two
wires that attach the battery to the circuit
board.

3. Locate the ID wheels in the back case

and remove the screw from the X-shaped
retainer. Lift the retainer free from the
alignment holes in the case. Set the screw
and the retainer aside.

4. Lift both wheels and rotate each one so

that the desired numbers will be visible
through the ID window. Replace the
wheels by aligning the holes in the
wheels so that they fit over the raised
guide posts in the case. Check to see if
the desired numbers are visible through
the ID window.
Note: Be sure the transparent wheel is
positioned closest to the case with the
opaque wheel on top.

5. When the desired numbers appear in the

window, replace the X-shaped retainer by
aligning the two pins on the bottom of
the retainer with the small holes in the
wheel alignment guides. Press gently into
place.

20

6. Install the retainer screw. Do not over-

tighten.

7. Replace the back case and install the four

screws. Be sure that no wires are pinched
by the case edges when the screws are
tightened. Tighten the screws snugly but
do not over-tighten as this could strip the
plastic threads.

Battery Replacement

The MathMaster is designed to operate for
an average of five years on the factory­installed battery. When the display becomes
too dim to read, the battery should be
replaced with a CR2032 or equivalent bat­tery available wherever watch or calculator
batteries are sold.

Please read each step completely before
accomplishing it. A small phillips screwdriver
is required.

1. With the MathMaster face down, remove

the four small screws securing the back
case.

21

2. Remove the back case by lifting it and

rotating it to the left, and placing it back­side down next to the main case. (see fig­ure B). Be careful not to break the two
wires that attach the battery to the cur­cuit board.

3. Locate the battery and battery retainer.

Do not remove the battery retainer
screws.

4. Inserting a small screwdriver or similar

instrument from the left side near the

Number
wheels

Battery
retainer

FIGURE B

X-shaped retainer

Small screwdriver

Front of case

Lift & rotate
back of case

gently to left

Be careful not
to pull on the
battery wires
when case is
opened.

22

large post, gently push against the side of
the battery until it snaps out of its retainer.
Be careful not to break the wires connect­ed to the battery contacts. Lift the old
battery out and set it aside.

5. Install the new battery with Plus (+) side

up by placing it just to the right of the
battery retainer. Using a finger, carefully
press the battery toward the left, back
into the retainer until it snaps into place.

6. Replace the back case and install the four

screws. Be sure that the wires are not
pinched in the edge of the case. Tighten
the screws snugly; overtightening could
result in stripping the plastic threads.

7. Insure that the calculator works by turn-

ing it on and observing the display.

Do not dispose of the old battery by fire. It
could explode.

23

One Year Limited Warranty

The MathMaster calculator is warranted against
defects of workmanship and materials for one
year from the date of original purchase by the
user from Stokes Publishing Company or an
authorized SPC dealer. Should the calculator mal­function under normal use during the warranty
period, return it to SPC (postage paid) for repair
or replacement at SPC option.

The warranty is void if the calculator is damaged
by accident, unreasonable use, negligence, or
other causes not due to defects in workmanship
or materials.

Disclaimers: Any implied warranties, including,
but not limited to, the implied warranties of mer­chantability and fitness of use, are limited to the
one-year duration of this warranty. SPC shall not
be liable for the loss of the calculator, or other inci­dental or consequential damages, expenses or
costs arising from the use of this calculator.

Some states do not allow exclusions or limitations of
implied warranties or consequential damages; therefore
the above limitations or exclusions may not apply to you.

Remedies: This warranty gives you specific legal rights,
and you may have other rights that vary from state to
state.

STOKES PUBLISHING COMPANY

1292 Reamwood Avenue
Sunnyvale. CA 94089
Phone [phone] • Fax [phone]

Printed in USA SPC 9/95