1.3.5 Basic calculation rules of significant figur...
(1)While conducting addition or subtraction,the digits of significant figures in the decimal portions are only brought into consideration.The result should have no more significant decimal digits than the least number of digits counted earlier.For others with more decimal digits,rounding them off is always acceptable.Take one more decimal digit for calculation,and round off the final result according to the standard significant digits.For example,1.2345+3.456-4.18+13.2≈13.7.
(2)While conducting multiplication or division,the least digit of significant figures(considering the number as a whole,not just the decimal portion)determines the digit of significant figures in an answer.Round the others with more significant digits off.Take one more digit for calculation then round off the final result based on the standard significant digits.For example,
(3)While conducting exponentiation,extraction of root,logarithm operation and others,the digit of final result should be consistent with that of the original value.For example,
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(4)The digit of constants(π,
,etc.)and intermediate results can be determined by following rules:take one more digit for calculation,and round off the final result according to the standard significant digit.The best way to implement the method of Banker’s Rounding.When the last digit stands more than 5,round it up to the nearest integer.If it stands less than 5,round it down no doubt.If the last digit stands at 5 precisely,round it up towards the nearest even integer.
