Review of Introductory Mathematics SIGNIFICANT DIGITSSIGNIFICANT DIGITSThis chapter presents the concept of significant digits and the application ofsignificant digits in a calculation.EO 1.8 DETERMINE the number of significant digits in a givennumber.EO 1.9 Given a formula, CALCULATE the answer with theappropriate number of significant digits.CalculatorUsage,SpecialKeysMost calculators can be set up to display a fixed number of decimal places. In doing so,the calculator continues to perform all of its internal calculations using its maximumnumber of places, but rounds the displayed number to the specified number of places.INV keyTo fix the decimal place press the INV key and the number of the decimal placesdesired. For example, to display 2 decimal places, enter INV 2.SignificantDigitsWhen numbers are used to represent a measured physical quantity, there is uncertainty associatedwith them. In performing arithmetic operations with these numbers, this uncertainty must betaken into account. For example, an automobile odometer measures distance to the nearest 1/10of a mile. How can a distance measured on an odometer be added to a distance measured by asurvey which is known to be exact to the nearest 1/1000 of a mile? In order to take thisuncertainty into account, we have to realize that we can be only as precise as the least precisenumber. Therefore, the number of significant digits must be determined.Suppose the example above is used, and one adds 3.872 miles determined by survey to 2.2 milesobtained from an automobile odometer. This would sum to 3.872 + 2.2 = 6.072 miles, but thelast two digits are not reliable. Thus the answer is rounded to 6.1 miles. Since all we knowabout the 2.2 miles is that it is more than 2.1 and less than 2.3, we certainly don’t know the sumto any better accuracy. A single digit to the right is written to denote this accuracy.Rev. 0 Page 53 MA-01
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