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FEATURES

Profit Analyzer.
TAX+/TAX–  Calculations
12 Digit Adjustable Display 
Last Digit Correction
Dual Power: Solar power with Battery Back Up

The DD-820 is a 12 digit desktop calculator with a special
                 feature that enpowers you to figure out
Cost, Sell & Gross Profit Margins quickly.  
It also calculates tax, tip,sur-charge added values of a fixed %
with the TAX+  TAX- analysis.

Profit Analyzer

DD-820

TM

TM

COST

COST

SELL

SELL

MARGIN

SELL

COST

MARGIN

MARGIN

GROSS PROFIT % (MARGIN)

You bought an item for $10.00.  
You sold it for 15.00
What is the Gross Profit Margin ?

10.00 

15.00 

You made 33.33 % profit.

SELLING PRICE (SELL)

You bought an item at
 
You would like to make 20% profit

This item should be sold for $ 15.00

BUYING PRICE (COST)

The item is sold at                                    90.00

The seller made 15% profit 

                25

How much was the cost for this item?    $67.50

TAX

TAX

 +

TAX

TAX

 +

COST

COST

SELL

SELL

MARGIN

SELL

COST

MARGIN

MARGIN

Profit Analyzer Keys

TAX CALCULATIONS

Setting TAX rate at 15%

   

The taxed price is $300

SETTING THE TAX RATE   

   138.00  (Total Tax )   

Once the TAX Rate is set, it will remain in memory until a new rate is entered

TAX

12.00

      20

The price is $120

120

Hold down   %    key for 3 seconds 
Key in rate     

TAX

 +

TAX

18.00 (Tax = 15% of 120 )   

TAX

 +

In order to see Tax amount
 press          again and you will see the amount of Tax

300          260.86 (The price before Tax)

In order to see Tax amount 
 press          again you will see the amount of Tax

  Tip,Tax, Surcharge Rate

Example

1

5

%

How much is the total bill including 15% Tax?

How much was the bill before Tax?

 39.14 (Tax Amount)

TAX Added

TAX Subtracted

TELEDEX Limited U.S.A. Warranty

TELEDEX INC. warrants these products to the original purchaser to

be free from defective material and workmanship. The product will

be repaired or replaced at our option, for up to one year when

returned with proof of purchase to the address below. Include a

check or money order for $3.00 to cover postage.

TELEDEX INC. 1 Atlas st. Kenilworth, NJ 07033         

Warranty valid only in the U.S.A.

Printed in China  5/00

Remove 3
Screws on
Back and
lift cover
off

+

Located battery
Holder

Slide battery to left
using small 
screw driver.
Then replace

PERCENT CALCULATION

Percentages (%)

Press

Displayed

p y

Example:
Calculate 6% of 100.

[1] [0] [0] x [6] %

6

Example:
Add 6% tax to $20.

[2] [0] [+] [6] [%]

21.2

Example: Calculate a 
20% discount from $150.

[1] [5] [0] [–] [2] [0] [%]

120

CONSTANT CALCULATIONS

Press = to repeat last function.

Example: 

xa

Calculate 5 x 5 x 5 x 5 + 2 + 2 = 629

Press [5]   [x]   [=]   [=]   [=]  [+]  [2]  [=] [=]

629

PERFORMING CALCULATIONS

Press

Displayed

p y

Addition (+)
Example: 6 + 7 = 13.

[6] [+] [7] [=]

13

Subtraction (–)
Example: 10 – 4 = 6.

[1] [0] [–] [4] [=]

6

Multiplication (x)
Example: 7 x 5 = 35.

[7] [x] [5] [=]

35 

Division (

÷

)

Example: 14

÷

7 = 2.

[1] [4] [

÷

] [7] [=]

2

(12 x –5)

÷

2 = –30 [

1][2][x][5][+/–

// ][

÷

][2] [=]

MINUS      

 30

152 + 38  =  190

[

1][5][2][+][3][8][=]        

                   190

78  –  22  =    56

[

7][8][–][2][2][=]           

                      56

22  x  12  =   264 

[

2][2][x][1][2][=]

                               264

312  

÷

  6  =     52 

[

3][1][2][

÷

][6][=]          

                        52

SIMPLE EQUATIONS

(F)Floating, Fixed(0,2,4), (A)accountant,
(A) Add. Mode, (0,2,4)

F 4 2 0 A

5/4

(  ) An answer is rounded up
(5/4) An answer is rounded off
(  ) An answer is rounded down

DECIMAL POINT SELECTOR

ROUND UP / DOWN SELECTOR

•     •     •     •     •

•     •     •  

Use backspace key         to delete the error digit.

LAST DIGIT CORRECTION

Every time the = key is pressed, the number in the
display is memorized and GRAND TOTAL appears in the
display. Press GT to display the sum of all memorized
numbers. Clear the grand total by pressing ON/AC.

Example:
Calculate   
A + B + C  
  
A = 6 x 7 
B = 5 + 4  
C = 22 – 5

GRAND TOTAL

GT

Press ON/AC to turn on the calculator. 
The calculator turns off automatically after 
about 12 minutes if no key is pressed.

TURNING CALCULATOR ON & OFF

ON

AC

OPERATING CALCULATOR

Changes the displayed number from positive (+) to 
negative (–) or from negative (–) to positive (+). 
– appears when the displayed value is negative.

+/– KEY

+/–

If the calculator is on, press ON/AC to reset the display to 0.

ON/AC KEY

ON

AC

Sets the number or digits that appear to the right of 
the decimal point in the display.  Example: 22 

÷

 7= ?

Switch 

 

  F 0 2 4 A 

Display  

3.14285. 3 

3.14 

3.1428  3.14

[6] [X] [7] [=]                      42
[5] [+] [4] [=]                        9
[2] [2] [–] [5]                      17

                                           68

GT

Press

Displayed

p y

Press

Displayed

p y

MEMORY CALCULATION

[M+]      Add the displayed number into Memory. 

             M appears in the display.

[M–]      Subtract the displayed number from Memory.

[MRC]   Displays the number stored in Memory. Press twice 

              to clear Memory. M disappears from the display.

BATTERY REPLACEMENT

CARE AND MAINTENANCE

USE ONE TYPE 389 BUTTON CELL BATTERY

www.datexx.com

•  Keep the calculator dry.  If it gets wet, dry it before use.

•  Store the calculator at moderate temperatures. 

•  Do not drop or strike the calculator. 

•  Clean the calculator case only with a soft damp cloth. 

   Do not use harsh cleaning solvents to clean the unit.

•  Keep the display and solar panel clean.

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