[. . . ] The calculator must not be covered when turned on, as this will cause it to overheat. Locations subject to quick temperature changes, high humidity and dirt should also be avoided. [. . . ] Tax minus key Calculates an amount excluding VAT with Tax rate preset by [RATE] key. Square root key Calculates the square root of the contents of the display. Delta percent key Automatically compares any two amounts and then calculates and prints the percent change. Gross Margin key From a known cost of goods and a desired gross margin, this key automatically calculates and prints the amount of markup and the selling price. Percentage key Completes percent calculation when [x] or [÷ ] key is used. Multiplication key To multiply, enter the first number (multiplicand) and press the [x] key; then enter the second number (multiplier) and press [=] key to obtain result. equal key Completes multiplication , division , delta percent or mark up. Division key To divide, enter the number to be divided (dividend) and press the [÷ ] key; then enter the second number (divisor) and press [=] key to obtain result. pressed twice , clears all the contents , including totalizer 1 , totalizer 2 and Grand Total totalizer. Decimal point key If the decimal point key is used more than once in a numeral, the first decimal point will be considered as effective. numeric keys Any numeral over 14 digits will be ineffective and will cause an error to be indicated. To subtract the same amount more than once (repeat subtraction), enter the amount once and press this key as many times as necessary. [. . . ] TO DISPOSE OF OUR DEVICES CORRECTLY: a) Contact the Local Authorities, who will give you the practical information you need and the instructions for handling the waste correctly, for example: location and times of the waste collection centres, etc. B) When you purchase a new device of ours, give a used device similar to the one purchased to our dealer for disposal. [. . . ]