初中全英课程学习-Decimals

PLACEVALUEWITHDECIMALSChapter1.2HowdoIknowwhatkindofdecimalitis?ThenameofadecimalisdeterminedbythenumberofplacestotherightofthedecimalpointNumberofPlacesDecimalNameExample1tenths0.72hundredths0.053thousandths0.016Whataremixeddecimals?MixeddecimalsarenumberswithbothwholenumbersanddecimalsThenameofawholenumberisdeterminedbythenumberofplacestotheleftofthedecimalpointInthenumber128.765,1isinthehundredsplace,2isinthetensplace,8isintheonesplace,7isinthetenthsplace,6isinthehundredthsplace,and5isinthethousandthsplaceHowdoyoureaddecimals?Toreadadecimalcorrectly,firstfindthedecimalpointWholenumbersaretotheleftofthedecimalpoint;anynumberstotherightofadecimalpointformadecimalfractionSay“and”forthedecimalpointThedecimal2164.511isreadas“twothousand,onehundredsixty-fourandfivehundredeleventhousandths”ZerosafterthedecimalpointWritingextrazerosafterthedecimalpointdoesnotchangethevalue!Thedecimals0.2,0.20,and0.200areequivalentdecimalsHEREARESOMEPRACTICEPROBLEMSINWHICHIWILLWORKTHROUGHWITHYOUTOMAKESURETHATYOUUNDERSTANDTHEMAINCONCEPTSCOVERED.PracticeExercise1Writethedecimals.1.Fivethousandths2.Ninety-fourthousandths3.Threehundredthirty-sixandsixty-ninehundredthsExercise2Writeeachdecimalinwords.1.7884.0112.5592.43.4.2034.612.2505.10.44Exercise3Inwhatplace(ontheplacevaluechart)istheunderlineddigit?Writetheanswer.1.1.4752.3.7633.7780.2154.412.4075.902.103Exercise4Writeadecimalthathasthesamenumber.1.0.22.5.513.410.64.753.809