EC-456 Dual-Powered Calculator
(650-0898)                 Operation                  Faxback Doc. # 18421

TURNING ON THE CALCULATOR

To turn on the calculator, simply Press ON CE/C.

NOTES:  The calculator automatically turns off about 6 minutes after you
        make the last entry.

        The calculator loses any pending calculations when it automatically
        turns off.

CORRECTING ENTRY ERRORS

If you enter an incorrect number, press ON CE/C once.  Then enter the
correct number and proceed with your calculation.

If you enter an incorrect function key (+, -, X, or /), simply press the
correct function key and continue.

CALCULATION ERRORS

ERROR appears on the upper right corner of the display when:

    A calculation result exceeds eight digits (this is an overflow error
    -- see "Estimating Calculation Results", below).

    A memory calculation exceeds eight digits (the memory contents remain
    unchanged).

    You try to divide by 0.

    You try to calculate the Square root of a negative number.

If ERROR appears, press ON CE/C to clear the error.

Estimating Calculation Results

If you perform a calculation that results in an overflow error, you might
be able to estimate the correct result (to eight significant digits) by
following this procedure.

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

2.  Remove the decimal point.

3.  Add as many zeros to the right of the number as there were digits to
    the left of the decimal point.

For example, if the display shows ERROR 1.0142064, the approximate answer
is 101,420,640.  If the display shows ERROR 319.70347, the approximate
answer is 31,970,347,000.

NOTE:  This is not always possible.  For example, adding
       99,999,999 + 1 = 1.0.

CALCULATION EXAMPLES

Basic Arithmetic

    You Press                  You See

    256 + 378=                 634.

    471 - 223=                 248.

    15.5 X 2.3=                35.65

    17.2 / 2.5=                6.88

Mixed Calculations

    You Press                  You See

    24 + 36 - 75               - MINUS
    X 8 / 9 =                  13.333333

Percentage, Add-On, and Discount Calculations

Calculation: 20% of 720

    You Press                  You See

    720 X 20%                  144.

Calculation: 30% added on to 540:

    You Press                  You See

    540 + 30%                  702.

Calculation: 20% reduction of 800:

    You Press                  You See

    800 - 20%                  640.

Constant Calculations

When doing multiplication calculations, the first value you enter is the
constant.

    You Press                  You See

    5 X 7=                     35.

    9=                         45.

    10=                        50.

For addition, subtraction, and division, the second value you enter is the
constant.

    You Press                  You See

    100 + 50=                  150.

    200 =                      250.

    300 =                      350.

    100 - 50 =                 50.

    200 =                      150.

    300 =                      250.

    100 / 50                   2.

    200 =                      4.

    300 =                      6.

Reciprocal Calculation

To find the reciprocal of a number, simply enter the number then press
/ and =.

    You Press                  You See

    8 / =                      0.125

Power Calculation: 7^6

    You Press                  You See

    7 X =====                  117'649.

Square Root Calculation

Calculation: The square root of 144.

    You Press                  You See

    144 (square root symbol)   12.

Memory Calculations

To store a value in memory, first press MRC (memory recall) twice to clear
the memory.  Then enter the number and press M+.

To add a value to the current memory value, enter the number or calculation,
then press M+.  The calculator totals the current calculation, and adds
that value to memory.

To subtract a value from the current memory value, enter the number or
calculation, then press M-.  The calculator totals the current Calculation,
then subtracts that value from memory.

To recall the value from memory, press MRC.

Calculation:

    2392 + 576
    _________  - 73 = -64.61582
    786 - 432

    You Press                  You See

    MRC MRC                    0.

                               MEMORY
                               786.

                               MEMORY
    432 M-                     432.

                               MEMORY
    2392 +                     2'392.

                               MEMORY
    576 /                      2'968.

                               MEMORY

    MRC                        354.

                               MEMORY
    -                          8.3841807

                               - MINUS MEMORY
    73=                        64.61582

Mark-Up Calculation

The mark-up function helps you find an item's selling price based on the
cost and the desired gross profit margin, and also lets you determine the
gross profit margin given the cost and selling price.

The Gross Profit Margin (GPM) is the percentage of the selling price that
is profit.

    Price - Cost
    ____________X 100 = GPM
    Price 

For example, if you want a gross profit margin of 20% on an item that cost
you $100, the selling price is $125 and the profit is $25.

    You Press                  You See

    100 MU 20%                 125.
    =                          25.

You can find the gross profit margin on an item that cost you $127 and
sold for 219.50:

    You Press                  You See

    219.5 - 127 MU             42.141231


(CD 11/2/95)