number cells - suffolk maths数的细胞-萨福克数学

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1、NumberCellsDrawa5-cellrectangleontheblackboardorOHP.GivemeanumbertogointhefirstcellNowgivemeanumberforthesecondcellCompletethefivecellsbyaddingconsecutivepairswithouttellingthepupilsyourrule.‘CanyouseewhatIamdoing?Repeatthiswithseveralmore5-cellrectang

2、lesInthiswayuntiltheruleofaddingconsecutivepairsiswellestablished.Avoidagreeingwith,orrejecting,theexplanationsofferedbypupils.Useyourresponsestoencourageallpupilstokeepthinking.Finally,asksomeonetoexplainthe‘rule’.Thiscanhelpboththe‘explainer’andanypu

3、pilswhoarestillindoubt.Drawanother5-cellrectangle.‘Givemeanumbertoputinthefirstcell.’‘Nowyouputanumberinthelastcell.’Tomakethenextchallengerelativelyeasy,makesurethatthesumofthefirstandlastnumbersisamultipleof3(youcanworkoutwhyyourself!).Itwillhelpifth

4、elastnumberissignificantlylargerthanthefirst.“Seeifyoucanfillinthethreeemptycells,usingthesameruleasbefore.’Encouragetrialandadjustmentandaskthepupilstoexplainwhytheychosetheirnumbers.Givepupilsplentyoftime—forthosewhofinishthisparticularchallenge,inv

5、itethemtochoosethefirstandlastnumbersforthemselves.Tryseveralmoreexamplesfortheclasswhereyouinvitethefirstnumberandplacethelastnumberyourself—don’tforgettomaketheirsumamultipleofthree!Itdoesappearthatthechallengetofillinthethreesquaresdoesdistractsomep

6、upilsfromtheoriginalrule.Otherpupilswillusuallycorrectthiswithoutteacherintervention.Wheneveryonehashadareasonablegoandmosthavetastedsuccess,moveontoask.~Howareyousolvingthese?Isthereamethodyoucandescribetoothers?’The-mostlikelyresponseis:‘Firstmakeagu

7、essforthenumberinthesecondsquare.Ifthisproducesalastsquarethatistoobig,tryagainwithasmallernumberinthesecondsquare.Don’tbesurprisedbymoresophisticatedmethods.Whenpupilsappearhappywithfillinginthemiddle3numbers–moveon.Trythefollowingonsomenew5celldrawin

8、gs.Givemeanumberforthefirstcell;givemeanumberforthelastcellFindthenumbersfortheotherthreecellsRepeatthisprocessItisalmostcertainthatinthefirstfewexamples,therewillbeonethatDoesn’thaveasumwhichisamultipleofthree-ifnot,makeoneupyourself.M