EC-453 (650-0920) Operation Faxback Doc. # 15143 TURNING THE CALCULATOR ON AND OFF Press ON or CE/C to turn on your calculator. Press OFF to turn it off. Notes: The calculator automatically turns itself off if you do not press any key for about 7 minutes. The calculator clears all previous entries, except values stored in memory, when it is turned off. USING THE +/- KEY Press the +/- key to change the sign of the displayed number. CORRECTING ENTRY ERRORS If you enter an incorrect value, press CE/C once, then enter the correct value and proceed with your calculation. If you press an incorrect function key (+, -, x, or divide), simply press the correct function key and proceed with your calculation. CALCULATION ERRORS E (error) appears at the lower left of the display when: A calculation result exceeds eight digits. This is an overflow error. 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 E appears, press CE/C to clear it. Then re-enter the calculation. ESTIMATING CALCULATION RESULTS If you perform a calculation that results in an overflow error (except adding a positive integer to 99,999,999), you can estimate the correct result (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 to the right of the number as many zeros as there were digits to the left of the decimal point. For example, if the display shows E1.0142064, the approximate answer is 101,420,640. CALCULATION EXAMPLES Basic Arithmetic Calculations Calculation You Press You See 256 + 378 = 634 256 [+] 378 [=] 634. 471 - 223 = 248 471 [-] 223 [=] 248. 15.5 x 2.3 = 35.65 15.5 [x] 2.3 [=] 35.65 17.2 divided by 2.5 = 6.88 17.2 [divided by] 2.5 [=] 6.88 Mixed Calculations Calculation You Press You See (24 + 36 - 75) x 8 24 [+] 36 [-] 75 [x] divided by 9 = -13.333333 8 [divived by] 9 [=] -13.333333 Percentage, Add-On and Discount Calculations Calculation You Press You See 20% of 720 is 144. 720 [x] 20 [%] 144. 30 % added on to 540 [+] 30 [%] 702. 540 is 702. 20% discount of 800 800 [-] 20 [%] 640. Constant, Reciprocal, Power, and Square Root Calculations (For multiplication, the first value you enter is the constant. For addition, subtraction and division, the second value is the constant.) Calculation You Press You See 5 x 7 = 35 5 [x] 7 [=] 35. 5 x 9 = 45 9 [=] 45. 5 x 10 = 50 10 [=] 50. 100 divided by 5 = 20 100 [divided by] 5 [=] 20. 200 divided by 5 = 40 200 [=] 40. 300 divided by 5 = 60 300 [=] 60. 1/8 = 0.125 8 [divided by] [=] 0.125 7^6 = 117649 7 [x] [=] =] 117'649 [=] [=] [=] Square root 9 = 3 9 [square root] 3. Memory Calculation To store a value in memory, first press MC (memory clean) once to clear the memory. To add a value to the current memory value, enter the number or calculation you want to add and 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 you want to subtract and press M-. The calculator totals the current calculation and subtracts that value from memory. To recall the value from memory, press MR (memory recall) once. Markup Calculations The calculator's markup function helps you find the selling price of an item based on the cost and the desired gross profit margin (GPM), and also lets you determine the GPM when given the cost and selling price. The GPM is the percentage of the selling price that is profit. Price - Cost (Profit) ----------------------- = GPM Price Annuity Calculation If you deposit $12,300 each year for six years at 6% annual interest, what is the annuity amount at the end of six years? Calculation You Press You See (1 + 0.06)^6 - 1 1 [+] 0.06 [x] [=] [=] ____________x 12300 [=] [=] [=] [-] 1 [divided by] 0.06 0.06 [x] 12300 [=] 85'796.394 =85796.394 (LB/all-05/05/95)