Unit #1Unit #2Unit #3Unit #4Unit #5Unit #6Unit #7Unit #8Unit #9Unit #10
spacerUNIT # 1  
spacerspacerIntroduction
spacerspacerObjectives
spacerspacerReading

spacer1.1
Metric
spacerSystem
spacerSI System
spacerBritish System

spacer1.2 Temperature
spacerMeasure-
spacerments

spacer1.3 Scientific
spacerNotation

spacer1.4 Dimensional
spacerAnalysis

spacer1.5 Precision,
spacerAccuracy,
spacerUncertainty

spacerLimitation of the Measuring Instrument
spacerAnalysis of the Limitation of a Ruler
spacerAnalysis of the Limitation of another Ruler
spacer1.6 Significant
spacerFigures

spacerThe Magnitude and Reliability of the Measurement
spacerFive Rules for Determining the number of Significant Figures in a Measurement

spacer1.7 Calculations
spacerInvolving
spacerSignificant
spacerFigures
spacerRules for Rounding off Numbers
spacerRules for Addition  and Subtraction

spacerRules for Multiplication and Division

spacer1.8 Density
spacerDensity and Temperature
spacer1.9 Specific
spacerGravity
spacerspacerProblems
spacer1 | 2 | 3
   

MEASUREMENT

1.7 - Calculations Involving Significant Figures

1.7.1 - Rules for Rounding off Numbers

Rule 1. If the digit to be dropped is less than 5, drop that digit and all other to the right of that digit. eg - Round off 86.0234 g to 3 significant figures. 86.0 g
 
Rule 2. If the digit to be dropped is greater than or equal to 5, increase the value of the last digit retained by one. eg - Round off 0.06587 L to 3 significant figures. 0.0659 L
 
Rule 3. If the digits to be dropped are to the left of the decimal point, zeros are used as their replacements. eg 1- Round off 1780.1 m to 4 significant figures. 1.780 x 103 m OR m
Do not leave it as '1780 m' as it is confusing.
  eg 2 - Round off 25,369 g to 3 significant figures. 2.54 x 103 g OR g
 

Additional Rule* If the digit to be dropped is 5 and is followed by zeros, drop the 5 and
(i) keep the last digit as is if the digit before the '5' is even, or
(ii) increase the last digit by 1 if the digit before the '5' is odd

* This rule is strictly applied if you are doing round off of statistical data as it prevents consistent rounding up of the data. For this course, this rule is not strictly enforced.
eg 1 - Round off 47.250 g to 3 significant figures. 47.2 g
eg 2 - Round off 47.350 g to 3 significant figures. 47.4 g

Section 2.6
Mathematical Operations Involving Significant Digits ..p23

 

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