Engineering Principles V11

Clive W. Humphris

NUMBER CONVERSION: Rounding Numbers.  

The number of decimal places is the number of figures after the decimal point. It is normal to round a decimal number to n decimal places to make it more readable. Obviously this reduces the accuracy of the original number.

The process of manual number rounding is to look at the next figure after n, (this is the decider figure) if the decider is five or greater, increase the preceding figure by one. Discard any figures after n.

Rounding numbers containing decimal fractions to whole numbers can be useful when estimating. The accuracy of the estimate will depend largely on the magnitude of the whole number relative to the fractional part.

For example, the fractional part of the value 2.4 has considerably more significance than say, 120.4. Estimating by rounding provides is a useful check on the value of the final calculation.

Table of contents

previous page start next page