Precision refers to the closeness of a set of values obtained for identical measurement of a quantity. Precision depends on the limitations of measuring devices and the skills with which it is used. However, accuracy refers to the closeness of a single measurement to its true value. The digits in a properly measurement are known as significant figures. these are meaningful digits in a measured or calculated quantity. The greater the number of significant figures in a reported result, smaller is the uncertainly and greater is the precision. the zeros at the beginning are not counted. the zeros to the right of a decimal point are counted. in the numbers that do not contain a decimal point. "trailing" zeros may or may not be significant . the purpose of zeros at the end of anumber is to convey the correct range of uncertainly. If we add 296.2 and 2.256, we get the answer as 298.456g. The number of significant figures in the result are: