QUY T ic TIM so Dll TRONG PHtP CHIA MJIT sli THJlP PHAN CHD l«OT St TD N H K N VA GHD MOT S l THAP PHAN 0 TifU HDG O ThS 06 TH| PHLTONG T H A O '''' dn 5 Id chuong Hnh m6l vd phi>c tqp cl^l vdi hpc sinh[.]
QUY Tic TIM so Dll TRONG PHtP CHIA MJIT sli THJlP PHAN CHD l«OT St TD NHKN VA GHD MOT Sl THAP PHAN TifU HDG O dn Id chuong Hnh m6l vd phi>c tqp cl^l vdi hpc sinh (HSJ Trong phdn s6 hpc HS bit ddu dupe Idm quen vdi cdc khdl nl$m mdl nhu: phdn sii, s6'lh$p phOn vd cdc phip Hnh /rSn t^p hqp sd' ai6i c6p tl^u hpc HS dang glol dopn chuydn dfin ti> tu Iri/c quan sinh d^ng song tu trt>u tupng nSn l6 chi>c hudng dfin cho HS hinh thdnh nhOng kl^n thi>c mdl mft cdch sdu sic vd hl^u bdn chdt Id v l ^ Idm khdng don gldn 0 dl Hch thuong vd sdchla 1) Defl vdi sv Chung Idl tidn hdnh khdo sdt 1.327 SV hd DHSP Tidu hpc ciio trudng OH (Thdi Nguydn, Hdl Phdng, Hud, Dd Ndng, HOng Vuong, Vinh, Tdy Sdc, Hd N$i, Hd N * ! II) vdi cdu hdl: 'S6 du cOa phip chia 429,5:2,8 vH Ihuong Idsih, nhltn Id stSndot a) 11; h) 1,1; c/ 0,11" Kdt qud: Chi cd d SV (chldm 35%) chpn ddp dn dung sd du 1,1 Cdn l p U SV (ehldm 37%) ehpn ddp dn sol Id s i du 11 holfc 0,1 vd 3dd SV (ehldm 28%) khdng chpn ddp dn ndo Sd lidu trdn eho thdy, sd lupng SVSP Hdu hpc ndm chdc kidn ihtk vd phdp ehio cd du cdn hpn chd (ehldm 35%) Trong dd, SVSP lldu hpc Idm sol h o ^ chua ndm chdc kldn ihuc ndn khdng ehpn ddp dn ndo ( e h i ^ d5%) Khi dupe hdi vd cdch Hm sd du phdp chia, da phdn SV ddu khdng Idm dupe Hdu hdt SV Hm dQng dupe sd du phdp chlo ddu bdng cdch Idy sd b| chia hi> dl Hch eOo thuong vd sd chia 2) Did ydl hfc vltn (HV) Id GV dl hc^^ qud khd quan hon Qua khdo sdt 128 HV cda ldp hd OH vOa Idm vOa hpc eOa trudng DH Hdi Phdng (DH Kldn An Kl vd DH Thdi BInh Kl 0) c6 HV da gidng dpy Todn khdl , (35,1d%); 5d HV tham gla gidng dpy Todn khdi , 2, (43,75%) Cdn Ipi HV khdng tham gla gidng dpy Todn (21,09%) Trong dd nhSng HV dd tOng dpy Todn khd'l , trd Idi diing Id / (91,11%) Nhdng HV tham gla gidng dpy Todn khdi , , lid ldl dung Id 1 / d (19,64%) NhOng HV khdng tham gla gidng dpy Todn Ird Idl dung Id / (7,41%) NhOng G V Hm dOng dupe kA qud phdp chia ndy ddu thvc hldn vd hudng ddn HS Ihpc hldn bdng cdch dOng ihudc kd ddng thdng *Tn«l|l|ik|clUiPMi| Tap chi Blip due s6 pn i • lo/iaiio Id dd'u p h l y cuo s l bj chlo x u i n g so d u sou d d ddt ddu phd'y cOo s l d u diJng vj h-i cuo dudng t h i n g d d dupe ddng xud'ng, khuylt e h l ndo ta thdm so khdng vdo vj trf d d thi dupe s l d u Khi dupe phdng vd'n, h l u h i t cdc GV d i u eho rdng cdch tim s l d u phdp chlo dd Id hp hpc hdl kinh n g h l | m h> nhung GV dgy trudc dd M | l so ft thi eho r i n g hp d d dgc dupe trdn mdt bdl bdo d Tgp ch! Todn hgc Ngodl ro, da s l d i u eho rdng khdng cd tdl ll^u ndo hudng dSn Quy l i e Hm sd' d u Irong phdp chlo / K / i t a A^STPc/ioAiSTN Trong Todn , b d l : «Chla MSTP cho MSTN' (trg 13) cd dua ro vf dy ve phdp chlo h i t vd tu d d hinh thdnh quy tdc eho HS Mud'n chia MSTP cho MSTN ta Idm nhu sau: - Chia phin nguy^ cOa sd' bj chia cho si chia; - Vlit ddy f^dy vdo bin phdl ihuong dd hm duoc hvdc Idil Idy ehff si diu Mn d p/idn thdp p/)dn cOa sd bf c/i/o di tiip fyc th\/e hlin phip chia; - Tl^ fyc chia vdi h>ng chu sd'dphin th$p phdn cOa sdbl chia Bdl «luyin tip'[\r 6A] dua vi dy: a) Dd dupe gldl mau 22.44 18 44 1.24 84 12 Trong phdp chia ndy, thuong Id 1,24, s l d u Id 0,12 Thu Ipi: 1,24 x 18 + 0,12 = 22,44 b) Ydu cdu HS tim s l d u cOo phdp chlo tuong ty Tim so d u cuo phdp chlo sou: 43.19121 19 "27J5~ 14 N h u vdy, bdng cdch nhdn xdt tuong ty, HS cd t h i thd'y phdp chia vf dy b cung g l l n g VI dy a d c h i s l b j chia Id so thdp phdn cd p h l n nguydn cd chi> so v d p h l n th^p phdn cung ed ehu so; d i n g thdi so chia Id s l ed hoi ehu sd*; vd thuong Id MSTP Irong d d phdn nguydn ed ehl? so vd phdn thdp phdn eung cd chu s l ; s l d u c | t td sd' ed hal chd s l gid'ng nhou Vi vdy, phdp chia ndy da s l HS d i u tuemg ty tim dupe k i t qud ehinh xdc s l d u cuo phdp diladdld:0,14 Tuy nhldn, n l u G V thoy d l l s l bj chia dl mpl chOt, VI dy , : 21 hay , : 21 thi p h l n Idn HS d i u rd't lung tung dl tim s l d u phdp chia ndy Hou h i t GV vd HS dupe phdng vd'n d i u eho r i n g HS thudng gdp khd khdn thyc hl^n phdp chia ndl trdnid hg khdng b l i t edeh (hay quy t i c } tim s l d u phdp chlo MSTP eho MSTN 2) Chia MSTP cho MSTP Trong Todn bdl: «C/)ta MSTP cho MSTP" (tr 71) SGK dua ro vf dy v l phdp chlo h i t cuo s l thdp phdn cho s l t h | p phdn TCr d d hinh thdnh quy tdc chia MSTP cho MSTP: Muin chia MSTP eho MSTP ta Idm nhusau: • Dim xem cd bao nhliu chffsidphin rfidp phdn ciJo sd' chia thi chuyin dd'u phdy d si bl chia sang bin phdl bdy nhiiu chff si; - Bd ddu phdy d sd bi chia ril rfiyr hlin phip chia nhu chia cho sih/nhlin Bditip [tr7\]:«MaymSibi qudn hit 2,8 m val Hdl ed 429,5 m vdi thi may duoc nhliu nhH bao nhliu bi quan nhu thivd cdn thOa mdy mit vdi?" Di gldl bdi todn ndy HS sd dua v l tim t h u o n g v d so' d u t r o n g p h d p chlo 429,5 : 2,8 Theo dung quy t i c HS se dua phdp chlo hal s l thdp phdn v l phdp chia hal so ty nhldn, vd cung mdt edeh h i t sue ty nhldn HS se tim s i d u phdp chia ndy nhu tim s l d u Irong phdp chlo hoi so ty nhldn Neu nhu vdy, phep chlo , : 2,8 sd dupe c h u y i n ve phdp chia : vd luc ndy s i d u sd Id 11 md thyc chit k ^ qud dung cOa phep chlo ndy so d u phdi Id 1,1 N h u vdy, GV mud'n hudng dan cho HS tim dung s l d u phdp chia s l thdp phdn cho s l thdp phdn thi cdn phdl cd thdi gian hinh thdnh eho ede em m | t k i l n tht/c mdi dd Id quy t i e Hm so d u phdp chlo s l thdp phdn cho so thdp phdn ( p h l n ndy hodn todn khdng dupe d l cdp phan hinh thdnh k i l n thue mdi} Vdi thdi lupng phut vua d l hinh thdnh phep chia h i t MSTP cho MSTP vd hinh thdnh phdp chia cd d u eua MSTP cho MSTP mdt cdch sdu sdc cho HS Id bdi todn khd d l i vdi GV Ndn chdng, trudc cho bdi ldp dudi dpng mdl v l phep chia cd d u d d , chung ta ndn cho thdm m$t bdi mau d l GV cd thdi glan d l hudng d i n cho HS h l l u dupe bdn chd't cuo phdp ehla cd d u cua phdn so cho phdn s l Vf dy, Todn - bdi (tr 71) Idi gldl, HS phdl thyc hl§n phdp ehla 429,5 : 2,8 vd tim sd' d u phdp chia ndy vdi thuong Id s l ty nhldn Theo dung quy t i c HS sd dua phdp chia hoi s l thdp phdn ve phdp chia hal sd' ty nhldn : 28 To hdy cho HS nhdn xdt v l phdp chia ta vua thyc hl§n: Dung to phdl thyc hidn phdp Iwchi Blao due so ng GV tuong lol budc vdo nghl Ngodl ra, nhOng gidng vidn tham gla gidng dpy n>dn Todn ddo tpo GV Hlu hpc edn chO Thyc t l Irong SGK vd cdc sdch bdl t|p Todn nhllu bdl ydu e l u HS phdl thyc hl|n m | t cdch trpng quan tdm hon nOo din vl|c gl6p SV xdy thuin thyc nhang phdp chia ed du nhu trdn, dyng vd hinh thdnh nhdng kiln thue, ddp ung ydu c h I n g hpn (tr 72); Bdl lOp Todn (tr ) ; elu cOa thyc Hin gidng dpy P Luyln gldl Todn (tr 24), Chfnh vl v l y , vl$e hinh thdnh cho HS khd'i quy t i e Hm s l d u (1) TrAn DiCn Hi Jn (cliQ biftn) To^n vd pbavng phip phdp chlo cd du cuo s l t h | p phdn cho dvy hpc toin d (l£u h^c - Dy An phit tn^n Gifto viftn s l thdp phdn hay cOa s l t h | p phdn cho s l ty ti^u tiQC NXB Gido due H 2006 Til lifu tham khdo nhldn id mdt vi^c Idm c i n thilt Kit \ufyn Hudng dfin quy tic Hm s i d u i Dd Dinh Hoan (chu bien) Toin NXB Cidodifc, H.2011 phdp ehla MSTP dio MSTN hoy MSTP cho MSTP Dfi Dinh Hoan (chu bien) BAI tfp Toia t