EC-215 Sales Tax Calculator (650-0573) Operation Faxback Doc. # 19160 TURNING THE CALCULATOR ON AND OFF Press ON/C once to turn on the calculator, 0. appears on the display. Press OFF to turn off the calculator. NOTES: If you do not make an entry within about 6 minutes, your calculator automatically turns off. To turn it back on, press ON/C once. If a value was stored in memory before the calculator was turned off, M 0. appears on the display when you turn the calculator back on (see "Using the Memory Keys"). CLEARING ENTRIES To clear an incorrect entry and continue the current calculation, press ON/C once (0. appears), then enter the correct value and continue your calculation. To clear the display and begin a new calculation, press ON/C twice (0. appears), then begin the new calculation. If you press an incorrect function key (+,-,x,/) during a calculation, simply press the correct function key and continue your calculation. CLEARING AN ERROR MESSAGE E, indicating an error, appears on the lower left side of the display when: A calculation result exceeds eight digits (see "Estimating Calculation Results") A memory calculation result exceeds eight digits. NOTE: The value in memory remains unchanged. You attempt to divide a number by 0. You attempt to calculate the square root of a negative number. To clear E from the display, press ON/C once. Estimating Calculation Results If your calculation results in an overflow error, you can estimate the approximate 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 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 reads E1.0142064, the approximate answer is 101,420,640. USING THE +/- KEY NOTE: A minus sign (-) on the left side of the display indicates a negative value. Press +/- to change the displayed value from positive to negative or from negative to positive. USING THE MEMORY KEYS To store a value in memory press M R/C (Memory Recall) twice to clear the memory (if necessary), then enter the number or calculation and press M+. NOTE: M on the left side of the display indicates that a value is stored in memory. To add to a value in memory, enter the desired number or calculation, then press M+. The calculator totals your calculation and adds that value to memory. To subtract from a value in memory, enter the desired number or calculation, then press M-. The calculator totals your calculation and subtracts that value from memory. To recall a value from memory, press M R/C once. To clear the memory, press M R/C twice. The memory value appears on the display. NOTE: See "Memory Calculations" on Page 22 for examples of memory use. STORING THE TAX RATE The + TAX(SET) and -TAX(REC) buttons let you set, recall, and calculate tax amounts. See "Tax Rate Calculations" on Page 23 for calculation examples using + TAX and -TAX. Follow these steps to set and store a tax rate. 1. Press ON/C twice to clear the display. 0. appears on the display. 2. Enter the desired tax rate. 3. Press RATE. RATE appears to the right of the value on the display. 4. Press + TAX. TAX% appears to the right of the value on the display. 5. Press ON/C. 0. appears on the display. 6. To recall and display the current tax rate, press RATE and then -TAX. TAX% appears to the right of the value on the display. NOTES: To store a different tax rate, simply repeat these steps and enter a different rate in Step 2. Replacing the battery automatically clears any stored tax rate (see Faxback Doc. # 19157). CALCULATION EXAMPLES Basic Calculations Calculations: 256 + 378 = 634 Calculations: 471 - 223 =248 You Press 256 + 378 = You Press 471 - 223 = You See 634 You See 248 Calculations: 15.5 x 2.3 = 35.65 Calculations: 17.2/2.5=6.88 You Press 15.5 x 2.3 = You Press 17.2 / 2.5 = You See 35.65 You See 6.88 MIXED CALCULATIONS Calculation: (24 + 36 -75) x 8/9 = -13.333333 You Press You See 24+ 24 36- 60 75x -15 8/ -120 9= -13.333333 Percentage, Add-On, and Discount Calculations Calculation: 20% of 720 is 144 Calculation: 30% added to 540 is 702 You Press 720 x 20% You Press 540 + 30% You See 144 You See 702 Calculation: 800 discounted by 20% is 640 You Press 800 - 20% You See 640 Constant, Reciprocal, Power, and Square Root Calculations Note: When multiplying, the first value you enter is the constant. When adding, subtracting, and dividing, the second value entered is the constant. Calculations: 5 x 7 = 35 5 x 9 = 45 5 x 10 = 50 You Press You See 5 x 7 = 35 9= 45 10= 50 Calculations: 100 / 5 = 20 200 / 5 = 40 300 / 5 = 60 You Press You See 100 / 5 = 20 200 40 300 60 Calculation: 1/8 = 0.125 You Press You See 8/= 0.125 Calculation: 7 to the 6th power is 117649. You Press You See 7x===== 117'649 Calculation: The square root of 144 is 12 You Press You See 144(symbol) 12 Memory Calculations Calculation: (2392+576)/(786-432) - 73 = -64.61582 You Press You See M R/C M R/C 0. 786 M+ M786. 432 M- M432. 2392+ M2'392. 576/ M2'968. M R/C M354. - M8.3841807. 73= M 64.61582. Tax Rate Calculations Example 1: Calculate a 20% preset tax rate on $100 Calculation 1: Store a tax rate of 20% You Press You See 20 RATE 20 RATE + TAX 20 TAX% Calculation 2: Add 20% tax to 100, then review the tax value. You Press You See ON/C 0. 100+TAX 120.+TAX + TAX 20. TAX Example 2: Calculate the pretax value of $100, which includes 20% tax. Calculation: Find the original value before tax, then find the 20% tax value. You Press You See 100-TAX 83.333333-TAX -TAX 16.666666 TAX (PH/all-02/16/96)