Khoa hpc Giao dgc VAN DUNG DAY HOC PHAT HIEN VA GIA! QUYET VAN DE VAO DAY HOC SO THAP PHAN CHO HOC SINH itiP 5 l O a t v a n d e So thap ph ln I I mdt trong cac maeh k i ln thUe dupe gidi thieu trong[.]
Khoa hpc Giao dgc - VAN DUNG DAY HOC PHAT HIEN VA GIA! QUYET VAN DE VAO DAY HOC SO THAP PHAN CHO HOC SINH itiP TliS PHAM VAN CONG Tn/orng Ti4u hgc Van Cam, Himg Hd, ThIi Binh l.Oatvande So thap p h l n I I mdt cac maeh k i l n thUe dupe gidi thieu chuong trinh mon Toln Day I I mot van de rat mdi doi vdi hpe sinh Idp Cijng nhuele maeh kien thUe khie, nhiem vu eUa moi g i l o vien la phai b I n g ele eleh day khae giup hpe sinh nam dupe va van dung ele kiln thUe da hoe vao g i l i cac bai t o l n v l sd thap phan nhU doi vdi so t u nhien va phan so Tuy n h i l n viee lam khong p h l i de dang doi vdi tat d g i l o vien Dae biet, qua trinh bdi dUdng hoe sinh gi6i, viee day hpe so thap phan lai cang trd nen quan trpng bdi eae dang toan nang eao v l so thap p h l n rat phong phu va da dang Oe giup hpe sinh Idp n I m v l hieu duoe ele npi dung k i l n thufe ve so thap p h l n mot each hieu q u i , ehung toi xin gidl thieu mdt so npi dung v l day hpc so thap phan eho hpe sinh Idp bang phuong phap day hpe phdt hien vd gidi quyit vdn di Dac trUhg cua phUdng phap day hoc phat hien va gidi quyet van de 2.1.Dgctnmg Trong day hpe phdt hien va gidi quyet vdn de, thay g i l o la ngudi tao tinh hudng gpi van de, to ehUe dieu khien hpe sinh thue hien eae hoat ddng, cdn hpc sinh la ngUdi phat hien v l n de, hoat dong tUgiac, tich cue, ehud6ngva sing tao d l g i l i quyet van de Nhu vay, day hoe phdt hien va gidi quyet vdn dethv - Hpe sinh dUpe dat vao tinh huong goi vdn de ehU khdng p h l i dupe thong b i o tri thUe dudi dang cd san; - Hpc sinh hoat ddng t u gile, tfeh cue, ehu ddng va sang tao, tan lUe huy dong tri thUe va k h i nang di phdt hien vd gidi quyit vdn di, ehU khdng p h l i ehi nghe thay gilng mot eleh thu dong; - Mue dich day hpe phdt hien vd gidi quyit vdn di khdng ehi l l m cho hpc sinh ITnh hdi dUOe k i t q u i eua q u i trinh phdt hien vd gidi quyit vdn di ma cdn l l m eho d e em phat t r i l n k h i nang t i l n hanh q u i trinh nhu vly Hay ndi d c h khae, hpe sinh hpe duac bdn thdn viee hgc, 34 - Nhu vay, bdn chdt cua dgy hgc phdt hien vd gidi quyit vdn di I I qua trinh nhan thUc doe d I o cOa hoc sinh, dUdi su ehi dao, hUdng dan eua gilo vien, hpc sinh n I m dugc tri thUe v l each thUe hoat ddng tri tue mdi thdng qua q u i trinh t u lue g i l i quyet ele tinh huong cd van de 2.2 Cde mde dd dgy hgc phdt hiin vd gidi quyetvande Day hpc phat hi#n v l gili quyet van de ed the chia mde dp sau day: MUc ddi: Giao vi^n dat van de, neu d c h gili q u y l t van de Hpc sinh thUe hien elch g i l i quylt van de theo hudng dan eCia g i l o vlen Gilo vien danh g i l k i t q u i lam viee eCia hpc sinh (Ddi tUdng hpe sinh yeu) MUc 2: Giao vien dat van de, gpi y de hpe sinh tim each gili quyet van de Hpe sinh thUe hien each glcii quyet van de vdi suglup dd eua g i l o vien can thiet Giao vien va hpc sinh eung danh gia (Doi tupng hpe sinh trung binh) IVIUc 3: Glao v i i n eung d p thdng tin, tao tinh hudng gpi van di Hoe sinh phat hien va xle dinh van de n l y sinh, tU lUe de xuat ele g i i thuyet va lUa ehpn g i l i p h l p Hpc sinh thuc hi^n each g i l i quyet van de, Giao vien v l hpe sinh cCing danh g i l (Doi tuong hpe sinh khi) MUe 4: Hpe sinh t u luc phat hien van de nly sinh h o l n eInh eua mlnh hole eCia edng dong, lua ehpn van de p h l i g i l l quylt Hpe sinh g i l l quylt van de tU danh gia chat lUpng, h i l u q u i , eo y kiln bo sung cua hpc sinh d n t h i l t (Ddi tupng hpe sinh gidi) Mot so each tao tinh huong gui van de day hpc ve so thap phan 3.1 Xay dung tinh hudng cd van de tUthUc tiin Khi day hpc sinh hinh t h I n h d c kiln thufc mdi, g i l o vien d n dua nhCfng tinh hudng ed van de tCf thuc tien de giup cle em nhan thUe van de nhanh chdng va de dang hon Cle tinh huong n l y 6ugc dUa p h l i xuat phat tUthue tien va ed ehUa dung nhUng van de ve toan hpc V/'du: Khi day each thuehien phep cong ho/sdfMp K H G D SO 69, t h d n g - 1 >iat ien BUuphdn g i l o vien ed the dua b l i t o l n : Cit mdt spi d l y hai doan Bilt doan thU nhat ed dp dai 1,2m v l doan thU hai ed dp d l i 1,3m H6i spi day luc dau d l i bao nhieu met? Phdn tich: Spi day neu bai toan eo the ed that thue te - NhUng k i l n thUe hpe sinh d l cd: -I- CIch g i l i b l i toan ed van g i l i b I n g mot phep cong (Tinh tong dp dai cua hai doan day d t ra); + CIch viet ele sd dp dai dudi dang s6 thap p h l n , dd cle em b i l t v i i t ele so 1,2m v l 1,3m dudi dang sd tU nhiln (1,2m = 12dm va 1,3m = 13dm); -I- Caeh thue hien ph^p edng hai so tU n h i l n , do cle em b i l t thuc hien p h l p cong (12-1-13 = 25) -Tinh hudng dat cho hpc sinh d d l y II: CIc em p h l i tinh dupe tong dp d l i eua hai doan dupe d t tU spi d l y liJic d I u Hay p h l i thuc hien p h l p e6ng hai sdthap phan: 1,2 v l 1,3 -Djnh hudng d e h g i l i q u y l t van d l cua hpc sinh: -i-TU dp dal hai doan day d I u I I ele s6 thap phan, dd elc em se nghT d i n vile dUa ele sd v l v i i t dudi dang sd t u n h i l n de thUe hien p h l p edng hai sd t u nhien +TU k i t q u i cd ddn vj I I dm, ta se doi nguoe lai ve ddn vj la m ChUy: Hpc sinh ed the nghT d i n vi&c dUa d e sd t h I p p h l n 1,2 va 1,3 v i i t dudi dang ele p h l n so 12 13 t h I p p h a n — va ""O' thuc hien ph^p edng hai 10 10 p h l n so t h I p phan Sau tiep tue doi ele p h l n so thap p h l n dd viet dudi dang sd thap p h l n 3.2 Xdy dung tinh huong cd vdn de tiy cac kien thdc hgc thuiaig ngdy Sau hinh k i l n thCfe, n l u g i l o vien ehi dua b l i tap van dung true t i l p k i l n thUe vUa hpe thi se khdng ehu3 dung van de Nhimg n l u giao v i i n dua nhCfng bai tap (nlng cao) m l g i l i hpe sinh p h l i thue h i f n mdt sd bude tinh, dd cd bude phai van dung nhChig k i l n thUe da hoc thi se x u l t hien vdn di budc d c em p h l i g i l i quyet d d I I nhd lai nhUng k i l n thdc d l dupe hpe de van dung v I o g i l i b l i tap Vi du: Khi day b l i Viit sd dien tfeh dudi dgng so thdpphdn, g i l o vien ed t h i dua bai toan: Mdt hinh chO nhat cd ehu vi m Bilt ehilu d l i hdn ehieu rdng dm Hdi di^n tich hinh chUnhat I I bao n h i l u met vudng? Phdn tich:Di g i l i b l i tap nly, ngoli vile n I m duae elch ddi ddn vj d i l n tich vC/a dupe hpe, hpc sinh K H G D s ^ , thdng - 2011 -Khoa hpcGtdoduc cdn p h l i biet I p dung each tim nCfa ehu vi, eleh g i l l b l i t o l n dang "Tong - hieu" Tinh hudng ed van de d d l y I I : Cle em p h l i nhd lai each tfnh d i l n tich hinh ehU nhat, each giai b l i t o l n dang 'Tong - hilu"de tinh ehieu d l i , ehilu rdng hinh ehuf nhat 3.3 Tgo tinh hudng bdng each yeu cau hgc sinh dimg each tUOng tugidi quyit van de Khi day mdt so kiln thUe mdi, g i l o vien ed the hudng dan hoe sinh thdng qua mot kiln thUc tUong t u da duge hpe trUde do.Tinh hudng dua d day can dUa vao mdt k i t qua tuang tU ma hpe sinh da biet trude dd nham khol day niem tin vao k h i nang eua bin thin Vidu: Khi day b l i Phep trd hai sd thdpphdn, g i l o vien neu bai t o l n : Mdt spi day dai 2,4m Cat spi day t h I n h hai doan Biet dp dai doan thU nhat la 1,05m.Tinh dp dai spi d l y thU hai Phdn tich:Jii each thUe hien phep edng hai sd t h I p p h l n da duoe hoe ed the yeu cau hpe sinh ap dung eleh thUe hien de thUe hien phep trU hai sd thap phan -Tinh huong dat cho hpe sinh d day la: Cle em p h l i thue hien phep trU (2,4 -1,05) bang each thue hien tUOng tU eleh thue hien phep e6ng hai sd thap phan - Djnh hudng each g i l i quyet van de cua hpc sinh: -I- Phli dat tinh nhU ddi vdi phep edng hai sd thap phan; -I- ThUe hien phep trii nhU ddi vdi phep trU hai sd t u nhien; + Dat dau phay thang edt nhu dat dau phay thUe hien phep edng hai sd thap phan 3.4 Tgo tinh hudng bdng each Igt ngUpc van di Cung nhu eae maeh kiln thufc khae, day hpe ve sd thap phan, ddi mdt tfnh chat nao dd n l u dUpc l i t nguoe lai se tao mot eau ehua ehae dung Tinh hudng dua d day p h l i la mdt m l n h de d I o eua mdt menh de hay mdt su mau thuan vdi nhO^g tri thUe ed sin Vidu: Day Khdi niem so thap phdn: -TU menh de: Mgi hon sddeucd the viet dugedudi dang sdthap phdn, g i l o vien ed the dUa mdt cau khie nhU: Mgi so thap phdn diu ed thi viit dugc dudi dang hon so Phdn tich: Cau: Mgi hon so diu co thi viit dUgc dudi dgng sd thap phdn la mot m l n h d l dung Tuy n h i l n , cau dao lai Mp/ sd thap phdn diu cd the viit duge dudi dgng hon s6\ai la m p t c l u s a i - Tinh hudng dat eho hpe sinh la: Cd p h l i sd 35 Khoa hpe Gido dye - -NghlenWM thap phan nao eung ed the viet dupe dUdi dang hon hpc v l giup hoc sinh tranh nhCfng sai lam tUOng tU sd khdng? Vi du: Day; Cdeh tim so dU phep chia hai so thdpphdn -Djnh hudng eleh gili quyet van di eua hpe sinh: -1- Cle em ed the suy nghT dua vao cac k i l n thUc da duae hoe ve hon sd va sd thap phan: Phan nguyen eua hon sd ehfnh la phan nguyen cCia s6 t h I p phan Vl phan nguyen eCia hon sd ludn khae ma phan nguyen eua sd thap phan lai ed the bang Do do, cau sau I I mdt eau sai • Gilo vien dua elch thue hien phep chia: 12,5: 0,4 nhu sau: 12,5 pA -t- Cle em cung ed the dua mdt sd trudng hpp eu the sd thap phan khdng viet duac dudi dang hon sd nhu: 0,1 ; 0,23 ; 0,456 ; Va eung di d i n k i t luan cau sau la mdt eau sai -I- Vly: 12,5 :0,4 = 31,2 (du ) Gilo vlen hdi hoe sinh each thuc hien dd dung hay sai? 3.5 Tgo tinh hudng bdng each yeu edu hgc sinh khdi qudt hod vdn di Trong day hpe ve sd thap phln, g i l o vien eung ed the dua nhCftng ddi tupng eu the, yeu d u hpe sinh quan sat phan tich v l tim nhung net ehung cOa cac ddi tuong va tU khai q u i t hoa nhung tinh c h i t hay mdt khIi niem eu the.Tinh hudng dUa yeu eau hpe sinh khai q u i t hoa p h l i la nhijng kiln thUc rieng le da hpe trudc nhIm khae sau kiln thufc va phat t r i l n t u eho hpe sinh 01o|31,2 Phdn tich: Khi chia hai sd thap phan, hgc sinh rat de nham tim sd dU cua phep chia Cle em thudng eho rang sd d u d day eung gidng nhU sd dU phep chia hai sd t u nhien Do do, g i l o vien eo the dua tinh hudng sai lam nhU tren de ele em giai q u y l t -Tinh hudng dat eho hpe sinh la: Lam the nao de biet dupe each thUc hien tren I I dung hay sai? -Djnh hudng each g i l i quyet van de eua hpc sinh: -i-TUvj tri eua ehUsd d hang phan tram eua sd bj chia, do sd dU eCia phep chia p h l i I I 0,02 + Cle em eung ed the nhan sai lam b I n g elch Vidu: Day b l i Nhdn mot sd thap phdn vdi 10, 100, lay sd thuang nhan vdi sd chia rdi edng vdi sd du 1000, Viee day hpe t o l n khdng ehi I I day ele tri thUe v l kT - Sau gilo vien eho hpe sinh thUc hien eae phep nang toan hpc m l eon hinh va phat trien dhpe nhan mot sd thap p h l n vdi 10 v l mdt sd thap phan sinh phuong phap hpe, n l n g lue sing tao va nang life khie vdi 100 Giao vien y^u d u hpc sinh so sanh k i t gili quylt van de Do do, day hpe phat hien va gili qua eua mdi phep nhan vdi thUa so thU nhat tU dd yeu quyet van de la mdt nhufng phuang p h l p day d u hoe sinh khIi q u i t hoa bang eleh eho hpe sinh neu hpe can dupe phd bien rpng rai cle n h l trUdng elch nhin mdt sdthap p h l n vdi 1000,10000, phd thdng, tU d p tieu hpe Phdn tich: Khi hpe sinh b i l t dupe k i t q u i cOa phep T A I LIEU THAM K H A O nhan mdt sd thap phan vdi 10 v l 100 (ed the djch dau phay cua sddd sang ben phai hoae2ehQsd0), Nguyen Ba Kim, P/iUongp/idp day hpe todn, NXB cac em eo the khai quat hoa quy t i e nhan mdt Dai hpe SUpham, 2002 sdvdi 10,100,1000, La.Leene (Phan Tat D i e dich) Day hoc neu vdn -Tinh hudng dat cho hpc sinh la: Mudn nhin mdt sd thap phan vdi 1000,10000 thi se lam nhuthe nao? - Dinh hUcmg each g i l l quylt van de cua hoc sinh: + Cac em nhan thay, nhan mdt sd thap phan vdi 10 thi djeh dl'u phay sang phai ehU sd 0, nhan vdi 100 thi djeh dau phay sang phai ehCfsdO.TUdo elc em suy nghT v l rut ehi viee d i m sd ehuf sd sau sd de djeh dau phay sang ben phai 3.6 Tgo tinh hudng tUnhC/hg sai Idm thUcOig gap tinh todn Cung n h u d e dang t o l n khae, g i l i ele b l i t o l n v l sd thap phan hpe sinh eung thudng mac nhufng sai l l m khie Vile tao nhUng tinh hudng ehUa dung sai lam, yeu d u hpc sinh tim eho sai eCJng la mdt vile lam n h I m eung ed, khie sau k i l n thdc da 36 de, NXB Gilo due, 1977 Mot so vdn devi ndi dung vd PPDHmdn Todn, Tai lieu BDTX cho g i l o vien tieu hpe ehu ki 1997-2000 4.DUan phat trilngiao v i i n tieu hpe, Od/md/PPDH dtieu hpe,Tai lieu bdi dudng GV, NXB Gilo due, 2005 le Nguyen long ThU di tim nhiJmgPPDHcd hieu qud, NXB Gilo due, 2000 SUMMARY Teaching math is not just the teaching of mathematical knowledge and skills, but also the formation and development of learning methods, creativity and problem solving Therefore teaching problem identification and solving shall be made popular in schools, starting from primary K H G D s o , thdng - 1 ... dat cho hpe sinh d day la: Cle em p h l i thue hien phep trU (2,4 -1, 05) bang each thue hien tUOng tU eleh thue hien phep e6ng hai sd thap phan - Djnh hudng each g i l i quyet van de cua hpc sinh: ... luan cau sau la mdt eau sai -I- Vly: 12 ,5 :0,4 = 31,2 (du ) Gilo vlen hdi hoe sinh each thuc hien dd dung hay sai? 3 .5 Tgo tinh hudng bdng each yeu edu hgc sinh khdi qudt hod vdn di Trong day hpe... u s a i - Tinh hudng dat eho hpe sinh la: Cd p h l i sd 35 Khoa hpe Gido dye - -NghlenWM thap phan nao eung ed the viet dupe dUdi dang hon hpc v l giup hoc sinh tranh nhCfng sai lam tUOng tU