Abstract: There is disclosed a method and apparatus for rounding numerals according to the number of significant digits or a rounding interval. The method starts with entering a numerical value x to be rounded and the number of significant digits n or a rounding interval w. The entered numerical value x is stored in a first storage portion of the apparatus. The entered number of significant digits n or rounding interval w is stored in a second storage memory. The numerical value x stored in. the first storage portion is rounded in a digit place determined by the number of significant digits n or rounding interval w stored in the. second storage portion. The numerical value x is rounded while using the number of significant digits n or rounding interval w as it is.