TRtrONG DAI HOC DONG THAP Tao Chi Khoa hoc s6 13 (6 2015) / B E X U A T MQT SO HOAT D O N G GIUP H Q C SINH H I E U RO K H A I NIEM H A N G C H U C VA D d N VI TRONG D A Y H Q C TOAN 1 • ThS Phan Thi[.]
TRtrONG DAI HOC DONG THAP Tao Chi Khoa hoc s6 13 (6-2015) / B E X U A T MQT SO H O A T D O N G G I U P H Q C S I N H H I E U RO K H A I N I E M H A N G C H U C V A D d N VI T R O N G D A Y H Q C T O A N • ThS Phan Thi Hi$pn Tdm tat Khi hgc sinh tap dim, cde em thudng dim cdc sdmgt cdch liin tuc Vdi cdeh dim dm gidn do, hgc sinh khdng the nam vUng cdu triic cua hi thd'ng sdvd ldm the ndo di xdy dung ede nhom chuc, nhdm tram, Dieu ndy ldm cho hge sinh kho khdn vdi nhiing bdi todn so sdnh hai sdtif nhiin, sdp xip ddy sd vd thiic hien cdc phep todn sd hgc Trong bdi bdo ndy, chiing tdi de xudt hogt dgng cu thi nhdm giup hgc sinh hiiu rd han khdi niim hdng chuc vd hdng dan vi Cdc hogt ddng duac xdy dying theo hudng tich ctfc hoa hogt dgng nhgn thtic cHa hgc sinh Tic khda: ehue vd dtm vj, todn 1, cdu tgo so DatvS'ndd Vi tri cfla mdi chtf sd ttong mdt sd ddng vai trd quan trpng sd hpc, mpt nhffng mach kidn thtfc quan ttpng chtfdng tnnh todn hpc tidu hpc Mdi chtf sd' ttong mdt sd cd gid tri khdc nhau, vi tri efla mdi chtf sd' ttong mdt sd cd nhidu chtt sd' xdc dinh gid tri eua sd' dd ViSc hidu ro vi tri cdc chtf sd ttong rapt sd giup hpc sinh hinh thdnh cac sd ttf nhlSn, dl dang so sdnh cdc sd ttf nhiSn cd hai hay nhieu chtt sd, hinh cdc kl thudt cpng, trtf vd nhdn hai sd cd nhidu chtt sd ve sau Tuy nhiSn, viSc nhdn chung Id mdt khd khdn ddi vdi hpc sinh ldp Ngtfdc Iai, hpc sinh hidu dtfdc gid tri cua cdc chtt sd' khdc nhau, phu thupe vdo vi tri efla chung ttong mpt sd thl ngtfdi hpe se thtfe hien nhtfng phep tinh sd hpe cd bin vdi cdc sd Idn dS dang hdn Cdc ndi dung ndy dtfde thd hien rd ttong chtfdng trinh todn tieu hpc Trong dd, khdi niSm cdc hdng Id ndn tdng diu tien dd xdy dtfng cdc ldp vd day cdc npi dung neu ttSn Trong bdi bdo ndy, chting toi dd xud't mSt sd boat dSng day va hpc nhim giflp hpc sinh nim vttng ve cd'u tao sd vd phdn tich sd ttong pham vi todn ldp I Cu thd, bdi bdo de cap ddn boat dpng sau: - Phdt tridn khd ndng dS'm bdi ddn vi (ddm thSm 1) vd ddm bdi chuc (ddm tiiSm 10); - Dung sd dd cd'u tao phdn tich sS' dd vidt, gpi ten so cd hai chtf sd; - Bidu dien nhffng sd cd hai chtt sd nhtf Id stf kdt hdp gitfa chuc vd ddn vi hay tat cd ddn vi; '•'Khoa Gido due Ti^u hoc - Mam non, TrirSng Dai hoc D6ng ThSp - Vidt vd bidu dien cdc sd cd hai chtt so thdnh tdng eua chuc va ddn vi; - Thdnh ldp hai sdhdn kem mpt ddn vi vd mpt ehuc N$i dung bai hpc "Khai niSm hang chuc va ddn vi sach giao khoa Toan ** 2.1 Khai niSm hang chuc va ddn vi sach giao khoa Toan Cf ldp 1, hpc sinh dtfdc hinh thdnh khdi niSm, thtf ttf cdc sd ttf nhiSn thong qua phdp ddm va dtfdc chia tiidnh giai doan Giai doan thtf nhit hpc vd cde sd ttong pham vi 10 Cdc sd dtfdc hinh thdnh theo nguySn tic "dS'm thSm 1" Trong hS thdp phan, ngtfdi ta dflng 10 chtf sd , , 2, 3, , , , , 8,9 di danh dau 10 sd ttf nhien diu tiSn vd day bit dau ttf sd Sd dtfde hinh thdnh tten quan didm Id ddc tnlhg cua cde tip hdp rdng, day sau bai so Sd 10 phdi dung chtf sd vd de vidt Giai doan thtf hai hpc vd cdc so' Idn hdn 10 ttong pham vi 100, ttong trtfdng hdp cd nhidu dd vdt, ngtfdi ta khong ehi ddm titog vdt riSng 1^ md edn gpp cdc dd vdt lai Uidnh ttfng chuc (mtfdi) dd dem, "chuc Id mgt dan vi mdi, gSm mudi dan vf thudng", chuc Id "dan vi" bac cao hdn "ddn vi thtfdng" Viec hinh thdnh khdi niem "chuc" gdm cdc btfdc: - Btfdc 1: Lap nhdm vd chuyen ddi nhdm: 10 vdt riSng le ldm "nhdm bdc 1" hay nhdm "chuc" - Btfdc 2: Ldp sd dd cd'u tao sd - Btfdc 3: Dpc sd va ghi so bang chtt sd - Btfdc 4: Luyen tdp ve ciu tao sd vd phdn tich sd Dd ghi sd ngtfdi ta cung dung 10 chtt sd nhtf giai doan 1, thay ki hieu "bdc eua cdc nhdm bdng Tap chl Khoa hoc so 13 (6-2015) mUCflsiG DAI HOC D N G T H A P thli tu sdp xip cde chtt sd biiu thiic ghi sd" vdi qui tfdc "theo thtf ttf Idn din ttf phai sang ti^i theo hdng ngang, eac nhdm kd tie'p hdn kem 10 lin", vi tri cdc nhdm gpi Id hdng (kem theo tSn nhdm ttfdng flng), ttfc Id vi tri chtf sd diu tiSn flhg hdng dan vi, vi tri chtt sd thtf hai Id hdng chuc 2.2 MOt sdySu c^u hpc sinh c^n dat dtfcfc hpc khai ni$m hang chi^c va dcfti vi sdch giao khoa Toan - Dpc, ddm vd vidt sd pham vi 100, phan biet khai niem sd vd chtt sd - Bieu diSn dtfdc sd ltfdng cfla cdc ddi ttfdng ttong thtfc td bang sd - Bidt so sanh hai sd ttf nhien nho hdn 100, nhdn biS't dtfdc vi tri cfla chflng ttSn true sd - Nhdn bidt hdng chuc, hdng ddn vi, ciu tao thdp phin eua mpt sd co hai chtf sd, bidt ldp sd dd phdn tich sd ttong pham vi 100 - Thtfe hien dtfde cde ph6p cpng va phdp trtf khong nhd theo thudt tinh nhim vd viet cdc phep tinh ttong pham vi 100 dtfa ttSn phan tich sS' vd sd dd phdn tieh sd Cac hoat ddng (HD) day hpc HD 1: Phdt triin khd ndng dim bdi dan vi vd dim bdi chuc + HD 1: On tap eho hpc sinh phdn tich cde sd ttf ddn thdnh tdng cfla hai sS' VI du phdn tich sd = + = + hay = + = + + HD 2: Sdi todn: Lan cdm viin bi tay trdi va viin hi tay phdi Hoi Lan cd tdt cd bao nhieu viin bi? Sau hpc sinh trd ldi viSn bi, gido viSn htfdng din hpc sinh thay ddi gid thuydt sd vien bi d tay phdi lin Itfdt Id 2, 10 Sau dd, gido viSn ddt van dd cd nhttng cdch dS'm them nao? Ddm thSm 1, ddm them 2, dem them 5, ddm them 10 nhtf tiid ndo? Cdeh ndo nhanh hdn? + HD 3: Gido viSn ttang bi cho mdi hpc sinh cd hai cdi tui dtfng 40 khdi vudng (20 khdi mdt mdu) vd ySu ciu tat cd hpc sinh ngoi tai ban ke't ndi ede khdi vudng vdi Cho bidt ed bao nhiSu khdi cai tfli? Cd bao nhieu each dS'm cdc khdi vudng? Tiep theo, giao vien gidi thieu bo que tinh (10 que moi bd) vd dinh htfdng hpc sinh cd the ddm bdi 10 Vdy ttfdng djf, ta cd the ddm bdi 10 cho cdc khdi vudng d tten Gido viSn khang dinh kdt qua gidng vdi kS't qud dS'm theo tiifng ddn vi (1, 2, 3, 4,-, 40) nhitog rd rdng nd nhanh hdn + HD 4: Gido vien yeu ciu mdi hpc sinh Id^y 10 que tinh (1 bd) vd khdi vuong Hdi hpc sinh cho biS't ke't qud cd td't cd bao nhiSu dd vdt? (hpc sinh nSu 12 vd khdng cin ddm) Giao viSn tdng kdt 12 gdm 10 vd hay chuc vd ddn vi + HD 5: gido vien eho hpc sinh mdt sd'ttfdng iJng so' dd vat cd sd Itfdng ldn hdn 10 vd yen ciu hpc sinh tdeh ehung thdnh cdc nhdm ttong dd cd nhdm 10 Vi du: 35 ddm la 10, 20, 30, 31, 32, 33, 34, 35 hay 10, 20, 30, 35 + HD 6: Yen cau hpc sinh khoanh ttdn nhdm cd sd Itfdng 10 cu cd rd't d Hinh vd ghi sd cu cd rdt vdo chd tto'ng Cd cfl ca rdt Hinhl + HD 7: Stf kdt hdp mSt sd tao bdi chuc vd ddn vi Hinh 7\ 20] _ : : o Hinh 111 TRUCJNG DAI HOC DONG THAP Tap Chi Khoa hoc s6 13 (6-2015) HD 2: Sa ditng sa dS edu tgo vd phdn tich so di ghi sd vd ggi ten sd co hai chU sd + HD 1: Gido vien ddt vin dd "Sd 17 gdm bao nhieu chuc vd bao nhieu ddn vi?" Sau hpc sinh ttd ldi chuc vd ddn vi, gido vien htfdng din vidt sd' (dai dien cho 10) vao cdt bSn ttdi vd sd (dai dien cho ddn vi) vao cpt bSn phai ttong sd phdn tich sau: Chuc Dtfnvi + HD 2: Gido vien cho hpc sinh thtfc hien ySu ciu sau dd cflng cd (Hinh 3) - ViSt sd chuc va ddn vi cd ttong cde sd ^ A Chuc cd Dcfnvi i C > k Chvic Dtfnvi Hinh HB 3: Biiu diin sdcd hai chUsdsdgdm hdhi chuc vd dan vi hay sd gdm todn dan vi + HD 1: n tdp lai cd'u tao so' vd dat van de sd gdm toan ddn vi - Cho bidt c^u tao cdc sd 34 va 43 vd viet chflng vdo sd dd phdn tich sau: Chuc D(Ai vi Chuc Ddn vi - Gido vien dat cau hdi gdi md vd mdi USn hS cfla vin dd: Sd 34 gdm md'y chuc va miy ddn vi? Cd bao nhieu ddn vi ttong chuc vd ddn vi? Hpc sinh tra ldi 34 ddn vi - Gido viSn ldm ro mdt sd cd the dtfdc phdn tich theo ciu tao thap phdn hay thdng thtfdng (eac ddn vi) - Gido vien cho hoc sinh ttf tim hidu cdc dirdng hdp sd cd chtf sd ttfdng ttf khac vd ttf rut nhan xet -I- HD 2: Giao vien cho hpc sinh thtfc hiSn cdc bdi todn sau (ffinh 4) - Vidt cdc sd va hodn thdnh cdu sau — bong hdng - Nd'i hinh ttfdng litig chuc ddn vi Id gidng vdi ddn ^ - Nd'i cdc hinh ttfdng tfng; ooa 3 112 Chvc Dtfo vi 3 Tap chi Khoa hgc so 13 (6-2015) mUdNG DAI HOC DONG THAP chuc ddn vi chuc ddn vi 32 ddn vi Chuc Dtfn vi 37 ddn vi chuc vi Linh cd so chuc ldn hdn Loan nSn cd se co so but chi nhidu hdn Loan -1- HD 3: Giao vien cho hpc sinh luyen tip qua cdc bai tdp (Hinh 5) Bai tap Viet theo mdu 35 = 30-1-5; 27 = + ; 45 = + ; 47 = H 95 = + ; 87 = 88 = 19 = + ; 79 = + ; 98 = 28 = 99 = + ; Bai tap Dien sdvdo cdc vudng vd chS trdng - Dien vdo chd ttong: a Chvc DiAlvj Chgc Dtfnvi Huih4 HD4: Viet sdcd hai ehU sd thdnh biiu thiie phdn tich - tdng hap eUa sd tron chuc vd dtm vi + HD 1: Cdng sd cd mpt chtt sd vdi 10 - Gido vien ddt cau hdi: Sd ndo nhidu hdn sd5 mtfdi ddn vi? Hpc sinh ttS ldi chuc ddn vi hay mtfdi Idm ddn vi - Gido viSn gidi thiSu: ta cd + 10 = 15 (bit diu vdi 5) hay 10 + = 15 (bit diu vdi 10) - Gido viSn cho hpc sinh Iam ttfdng ttf cac sd pham vi 10 + HD 2: Cho hpc sinh ldm bdi todn: Linh cd chiec hgp, mdi hop dUng 10 but chi mdu vd cdy but chi mdu le Loan eo 19 cdy but chi mdu, ed dy bdo rang minh cd nhieu but cm mdu han Linh Linh ihdng ddng y Hdi bgn ndo ditng? Trong bdi todn, hpc sinh se bidu diSn sd cd hai chtt sd theo hdng chuc vd ddn vi dd so sdnh sd Itfdng bflt cin mdu De bidt ed nhieu bflt chi hdn, ta cin so sdnh sd hang chuc cfla bflt ehi efla hai ban trtfdc Tuy nhien, vin dd cd the gdy nham lln cho hpc sinh Id tai Loan cd nhidu ddn vi hdo Linh nhtfhg kdt qud eudi cung lai it hdn Bdi a a a a Chuc StfD vi ChMC Dtfnvi = 13 Bai t^p Dien sdvdo cdc vuong vd chd Hinh5 HD 5: Thdnh lap hai sdhan kim dcm vi vd ehue 113 T9P chi Khoa hoc so 13 (6-2015) TRUCJNG DAI HOC DONG THAP + HD 1: Hai sd hdn mdt ddn vi - Giao viSn: So 15 gdm may chuc va m i y ddn vi? - Hpc sinh: chuc va ddn vi - Giao vien: So ldn hdn sd 15 mpt ddn vi la sd miy? - Hpc sinh: Sd 16 - Gido viSn: Phat bieu edu? - Giao viSn: Yen cau hpc sinh vidt sd 15 vdo bang sd dd phdn tich - Hpc sinh: viet sd vao sd - Gido viSn: Sd nhidu hdn sd 15 mtfdi ddn vi Id sd miy? - Hpc sinh: Sd 25 - Gido vien: Hay quan sdt sd dd phdn tich sd (Sd dd 8) va cho bidt stf thay ddi? - Hpc sinh: Sd 16 nhieu htfti sd 15 mot ddn vi - Giao viSn: Hay quan sdt Sd va eho bidt cai ^ da thay ddi va cdi ^ khdng thay doi? + Chuc Ddnvi * Chuc Ddn vi 5 Stf - Hoc sinh: Cdt h^ng chuc da thay dSi tit chuc len chuc, hkng dtfn vi giii nguyen Stfdd6 - Gilo vi§n: Htfdng dSn hoc sinh nit qui - Hpc sinh: ket qua hdng chuc khdng thay tac c6ng them 10 ddi, chi thay ddi kdt qua hdng ddn vi + HD 6: TiTtfng ttf, chung ta hinh thknh qui - Giao vien: Mot ddn vi da thay doi ttf ISn tac triif di 10 ddn vi va ta chi cpng vdo cpt ddn vi + HD 7: Thifc hanh giai cac bM tap sau Ttf dd, gido vien hinh cho hpc sinh qui Bai t$p Thuc hien cdc phep tinh tac cdng khdng nhd gitfa sd cd chtt sd vdi sd ed chtf sd 12 25 45 35 + HD 2: TtfOng tif eho it hdn ddn vi Ttf dd, -10 1-10 gido vien hinh nen phep trtf khdng mtfdn -10 -20 chuc sd cd chtf sd vdi sd cd chtf sd + HD 3: Bai tap Viet sd thieh hap vdo Bai tSp Dien sd thich hop vdo d trdng trdng rdi dgc ede sd dd (Hinh 7) hi IH ; h l i i 1 hi (»K>C C-(SK>0®^C hi h l i l«l 1 hi Hiiib9 1 hi ' l«l M hi HiiihT -f HD 4: Nhieu hon 10 (it htfn 10) Gido vien cho hoc sinh gidi bdi todn; An cd cdy biit ehi mdu An mua them 10 cdy but mau; Binh cd 17 cdy bdt chl mdu nhitng ddnh mdt 10 cdy but chi mdu Hoi bgn ndoed sdedy but nhieu turn ? + HD 5: Hinh thknh qui tac cpng (Mng chuc) dtfa theo sd phkn Iich 114 Bai tap Dien ddu >,