EC-2028  (650-0526)              Operation             Faxback Doc. # 7959

CHECKING THE TIME

The EC-2028 automatically returns to the clock display.  If you do not
pres a button for 4 minutes.  To switch from the calculator display to the
clock display at any time, press TIME/SET.

USING THE CALCULATOR

To use the calculator, press CAL. 0 and .)))) appear on the display and
the voice announces "Reset."  Enter calculations in the order they appear
on paper (see "Calculation Examples"),  or try an arithmetic quiz (see
"Arithmetic Quizzes").

USING MUTE

Press MUTE to silence the voice announcement.  MUTE appears on the
display.  Press MUTE again to turn on the voice announcement.
.)))) appears on the display.

ADJUSTING THE VOLUME

The VOLUME 0/1/2/3 switch on the back of the calculator lets you set the
volume to a comfortable level.

CORRECT ERRORS

The EC-2028 displays ERROR when:

*  You attempt to divide a number by 0.

*  The calculation result exceeds eight digits to the left of the decimal 
   point.  This is an overflow error.

If you enter a calculation that causes an overflow condition, you can
figure out the correct answer (to eight significant digits) by following
these steps.

1.  Count the number of digits displayed to the left of the decimal point.

2.  Remove the decimal point.

3.  Add enough zeros to the end of the number to get a total of 8 digits, 
    then add as many zeros as there were digits to the left of decimal 
    point.

Examples
┌─────────────────────┬────────────────────┬────────────────────────┐
│    Problem          │   Display Reads    │       Approximate      │
│                     │                    │       Answer           │
├─────────────────────┼────────────────────┼────────────────────────┤
│ 96857431 + 4563211  │                    │  104'420'640           │
│ = 101,420,642       │ ERROR 1.0142064    │  (add one zero)        │
├─────────────────────┼────────────────────┼────────────────────────┤
│ 123456 x 25896      │ ERROR 31.970165    │  3,197,016,500         │
│ =3,197,016,576      │                    │  (add three zeros)     │
└─────────────────────┴────────────────────┴────────────────────────┘

Press CE/C once to remove ERROR from the display.  The voice announces
"Clear."  Then press CE/C again or CAL to clear the overflow display.


IF YOU MAKE A MISTAKE ENTERING A CALCULATION

The calculator performs the last function key pressed.  For example, if
you press 7 x divided by + 5 + =, the calculator preforms 7 + 5 =. 12
appears on the display.  To clear function entry errors, simply enter the
correct function.

To clear numeric entry errors, press CE/C once to clear the last digit you
entered, then enter the correct digit.

CALCULATION EXAMPLES

Basic Mathematic Calculations

┌──────────────────────┬──────────────────────────────┬──────────────────┐
│    Calculation       │        You Press             │  You See         │
├──────────────────────┼──────────────────────────────┼──────────────────┤
│123 + 456 - 789 = -210│   123(+)456(10/-)789(=)      │ MINUS  210       │
├──────────────────────┼──────────────────────────────┼──────────────────┤
│  78 x 45 divide by 23│78(ll/x)45(12/divided by 23(=)│    152.60869     │
│  =152.60869          │                              │                  │
├──────────────────────┼──────────────────────────────┼──────────────────┤
│17.2 divided by 2.5 = │  17.2 (12/divided by)2.5(=)  │     6.88         │
│   6.88               │                              │                  │
└──────────────────────┴──────────────────────────────┴──────────────────┘

Mixed Calculations

┌───────────────────────┬──────────────────────────┬───────────────────┐
│   Calculation         │     You Press            │      You See      │
├───────────────────────┼──────────────────────────┼───────────────────┤
│ 15.3 x 13.7           │    15.3(11x)             │           15.3    │
│ -----------  + 19-11  │    13.7(12/divided by)   │          209.61   │
│     4                 │                          │                   │
│                       │       4(+)               │         52.4025   │
│ =60.4025              │    19(10/-)              │         71.4025   │
│                       │       11(=)              │         60.4025   │
└───────────────────────┴──────────────────────────┴───────────────────┘

ARITHMETIC QUIZZES

Here is how you take an arithmetic quiz.

1.  Press CAL. 0 and .)))) appear on the display and the voice announces
    "Reset."

2.  Press +/?,-/?,x/?,divide/?, for the calculator to give you problems
    in addition, subtraction, multiplication, or division.  TEST appears
    on the display and the voice announces each equation that appears on
    the display.

3.  Enter the correct answer for each equation.  If the answer is correct
    the voice says "Correct" and O appears on the display.  If the answer
    is wrong, the voice says "Error" and X appears on the display.

NOTES:  You must enter an answer within 4 minutes.

        The EC-2028 automatically announces the correct answer after you
        enter three wrong answers.

        If you make a mistake when entering the first answer digit, press
        CE/C to delete the digit.  The voice repeats the equation once,
        and then you can enter the correct answer.

4. After each correct answer, a new problem appears on the
   display.

5. Press CAL or TIME/SET to stop the quiz.

ASCENDING/DESCENDING MULTIPLICATION TABLE

Follow these steps to see a particular ascending/desending multiplication
table.

1.  Press (Arrow loop to right or Arrow loop to left).  The voice
    announces "Practice ascending" or Practice descending" and x and =
    appear on the display.

2.  Press 12/divide, ll/x, 10/-, or 1-9 to see a multiplication table.
    The voice announces each equation in ascending (from 1 to 12) or
    descending (from 12 to 1) order and its correct answer.

Press CAL to return to the calculation mode.


(CJD/all-11/30/94)