To do simple arithmetic click the numbers and then press the sign for addition, multiplication, subtraction, or division. You can also type in the numbers and press + for addition, - for subtraction, * for multiplication and / for division. To view the answer press the button that is an =.
To make a number negative press the button that looks like a +/-. To insert decimals press the decimal point button which looks like . when you get to the part which is less than a whole number. To clear input from Kcalc Press the button with a C on it.