Rounding and estimating - KS3 Maths Revision - BBC Bitesize

Q1. Round 0.0724591 to 3 significant figures (s.f.). ChangelanguageEnglishCymraegGaeilgeGàidhligHomeLearnSupportCareersMyBitesizeAllBitesizeRevisequizTestprevious123456Page5of6nextRoundingsignificantfiguresThemethodforroundingtoagivennumberofsignificantfiguresisalmostidenticaltothemethodusedforroundingtoagivennumberofdecimalplaces.Lookatthenumberaftertheoneyou'reinterestedintoseewhetheritisgreaterorlessthan\(5\).Ifit'slessthan\(5\),rounddown.Ifit's\(5\)ormore,roundup.QuestionQ1.Round\(0.0724591\)to\(3\)significantfigures(s.f.)Q2.Round\(0.2300105\)to\(4\)significantfigures(s.f.)Q3.Round\(648,942\)to\(2\)significantfigures(s.f.)RevealanswerupdownA1.Toroundtothreesignificantfigures,lookatthefourthsignificantfigure.It'sa\(5\),soroundup.Therefore,\(0.0724591=0.0725\)(\({3}\)s.f.)A2.Toroundtofoursignificantfigures,lookatthefifthsignificantfigure.It'sa\(1\),sorounddown.Therefore,\(0.2300105=0.2300\)(\(4\)s.f.)A3.Toroundtotwosignificantfigures,lookatthethirdsignificantfigure.It’san\(8\),soroundup.Therefore,\(648,942=650,000\)(\(2\)s.f.)curriculum-key-factEventhough0.2300isthesameas0.23,includethezerostoshowthatyouhaveroundedtofoursignificantfigures.previous123456Page5of6nextStrugglingtogetyourheadroundrevisionorexams?Ourtipsfromexpertsandexamsurvivorswillhelpyouthrough.GetadvicehereLinksBBCPodcasts:MathsRadio4podcastshowingmathsisthedrivingforcebehindmodernscience.BBCRadio4:Mathscollectionexternal-linkMyMathsSUBSCRIPTIONexternal-linkBlutickexternal-linkNRICHMathsClubexternal-linkMathsWatchSUBSCRIPTIONexternal-linkUnioSUBSCRIPTIONKS3SubjectsKS3SubjectsupdownArtandDesignBiologyChemistryCitizenship(Wales)ComputerScienceDesignandTechnologyEnglishFrenchGeographyGermanHistoryHistory(Environmentandsociety)Humanities-Geography(Wales)ICTIrish–LearnersLearningforLifeandWorkMandarinMathsMediaStudiesModernForeignLanguagesMusicPhysicalEducationPhysicsPSHEandCitizenshipReligiousStudiesScienceSpanishWelshSecondLanguage ExploretheBBCHomeNewsSportWeatheriPlayerSoundsCBBCCBeebiesFoodBitesizeArtsTasterLocalThree