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Khoa hoc Gido due N g l n cu*u V A N D U N G C A C P H U O N G P H A P D A Y HOC T H E O D j N H H U O N G D O I M O I T R O N G M O N T O A N Of T R U O N G T R U N G H O C C O S O • PGS TS TON THAN[.]
Khoa hoc Gido due- Ngl n cu*u V A N D U N G C A C P H U O N G P H A P DAY HOC THEO D j N H HUONG D O I M O I T R O N G M O N T O A N Of T R U O N G T R U N G H O C C O S O • PGS.TS TON THAN - TS PHAN THj LUYEN Vien Khoa hoc Giao due Viet Nam T huc tien va li luan da cho thay, de thuc hien day hpc co hieu qua, GV can biet each tan dung nhdng uu the cua tUng phuong phap day hpc (PPDH), biet lua chpn phuong phap phu hpp vdi npi dung day hpc, phu hpp vdi dac diem va dieu kien cua giao vien (GV), hpc sinh (HS) va cua nha trudng Can ke thda va phat huy tdi da the manh cua cac phUdng phap day hpc (PPDH), sd dung cac trang thiet bi day hpc phu hdp nham lam cho HS chu dpng, tich cdc hdn hpc tap Sau day la mpt so PPDH dddc sd dung phd bien, cd hieu qua, cd kha nang dap dng dddc yeu cau ve ddi mdi PPDH mon Toan d trddng trung hoc cd sd hien Phuong phap van dap 1.1 Ban chat: PhUdng phap van dap la qua trinh tddng tac gida GV va HS dddc thdc hien thdng qua he thdng cau hdi va cau tra Idi tddng dng ve mpt chu de nhat dinh dddc GV dat Day la PPDH ma GV khdng trdc tiep dda nhdng kien thdc hoan chinh ma hddng dan HS td tdng bddc de cac em td tim kien thdc mdi phai hpc Can cU vao tinh chat hoat.dpng nhan thdc cua HS, ngudi ta phan biet cac loai: van dap tai hien, van dap giai thich minh hoa va van dap tim toi - Van dap tai hien: ddpc thdc hien nhdng cau hdi GV dat chi yeu cau HS nhac lai kien thdc da biet Loai vain dap chi nen sd dung han che can dat mdi lien he gida kien thdc da hpc vdi kien thdc sap hpc hoac cung cd kien thUc vUa mdi hpc - Van dap giai thich minh hoa dddc thUc hien nhung cau hdi cua GV dua cd kern theo cac vi du minh hoa (bang Idi hoac bing hinh anh true quan) nhim giup HS de hieu, de ghi nhd Viec ap dung phUdng phap cd gia tri su pham cao hon nhung khd hdn va doi hdi nhieu cong sUc cua GV hdn chuan bi he thdng cac cau hdi thich hpp - Van dap tim tdi (hay van dap phat hien): la 16 loai van dap ma GV sd dung he thdng cau hdi de kich thich sd tranh luan, trao ddi y kien gida GV vdi HS, gida HS vdi HS Thdng qua dd HS dan dan tiep can kien thdc mdi Trong van dap tim tdi, trat td logic cac cau hdi phai nhim din dit HS tdng budc phat hien ban chat sU vat, quy luat cua hien tupng, kich thich tinh tich cUc tim toi va long ham mudn hieu biet cua HS SU cong cua phUdng phap van dap phu thupc nhieu vao viec xay ddng ddpc he thdng cau hdi gpi md thich hdp (tat nhien phu thupc vao nghe thuat giao tiep, dng xd va dan dat cua GV) 2.2 Quy trinh thifc hien 1.2.1 Trddc gid hoc: - Bddc 1: Xac dinh muc tieu bai hpc va ddi tddng day hpc Xac dinh cac ddn vi kien thdc kT nang cd ban bai hpc va tim each dien dat cac npi dung dddi dang cau hdi gpi y, dan dit HS - Bddc 2: Dd kien npi dung cac cau hdi, hinh thdc hdi, thdi diem dat cau hdi (dat cau hdi d chd nao?), trinh td cua cac cau hdi (cau hdi trddc phai lam nen cho cac cau hdi tiep sau hoac dinh hddng suy nghT de HS giai quyet van de) Dd kien npi dung cac cau tra Idi cua HS, dd dd kien nhdng "Id hdng" ve mat kien thdc cung nhd nhdng khd khan, sai lam phd bien ma HS thddng mic phai Dd kien cac cau nhan xet hoac tra Idi cua GV ddi vdi HS Dd kien nhdng cau hdi phu de tinh hinh tdng ddi tdong cu the ma tiep tuc gpi y, dan dat HS 1.2.2 Trong gid hoc Bddc 3: GV sd dung he thdng cau hdi dd kien (phu hpp vdi trinh dp nhan thdc cua tdng loai ddi tdpng HS) tien trinh bai day va chu y thu thap thong tin phan hdi td phia HS Quy trinh dat cau hdi tren Idp thudng bao gdm cac budc sau day: - Dat cau hdi - DUng lai de HS cd thdi gian xem xet cau KHGD so 55, thdng - 2010 •Khoa hoc Gido due ghien cull hoi va suy nghi" cau tra Idi - Goi HS va nghe cau tra loi - Cho y kien danh gia ve cau tra Idi Co the tao dieu kien de HS khac nhan xet, danh gia cau tra Idi cua HS Tren cd sd nhdng cau tra Idi va y kien cua HS khac, GV cd the dat nhdng cau hoi, van de nham lam cho HS hieu sau sac kien thdc hon hoac din dat sang kien thdc mdi 1.2.3 Sau gid hoc GV chu y rut kinh nghiem ve tinh ro rang, chinh xac va trat td logic cua he thdng cau hdi da dddc sd dung gid day 1.3 Wu diem - Van dap la each thdc tot de kich thich td doc lap cua HS, day HS each td suy nghT dung din Bang each HS hieu npi dung hpc tap tot hon each hpc vet, thupc long - Gpi md van dap giup Idi cudn HS tham gia vao bai hpc, lam cho khdng Idp hpc soi ndi, sinh dpng, kich thich hdng thu hpc tap va long td tin cua HS, ren luyen cho HS nang Idc dien dat sd hieu biet cua minh va hieu y dien dat cua ngddi khac - Tao mdi trddng de HS giup dd hpc tap HS kem cd dieu kien hpc tap cac ban nhdm, cd dieu kien tien bp qua trinh hoan cac nhiem vu dddc giao - Giup GV tri sd chu y cua HS; giup kiem soat hanh vi cua HS va quan li Idp hpc 1.4 Han che - Han che Idn nhat cua phddng phap van dap la rat khd soan thao va sd dung he thdng cau hdi gpi md va din dit HS theo mpt chu de nhat quan Vi vay dpi hdi GV phai cd sd chuan bi rat cong phu, neu khdng, kien thdc ma HS thu nhan ddpc qua trao ddi se thieu tinh he thdng, tan man, tham chi vun vat - Neu GV chuan bi he thdng cau hdi khong tot, se dan den tinh trang dat cau hdi khdng ro muc dich, dat cau hdi ma HS de dang tra Idi cd hoac khdng Hien nhieu GV thddng gap khd khan xay ddng he thdng cau hdi khdng nim chic trinh dp cua HS, vi vay thddng sau dat cau hdi la neu gpi y cau tra Idi khien HS rdi vao trang thai bi dpng, khdng thdc sd lam viec, chi y lai vao gpi y cua thay, co giao 1.5 Mot sd luv y Phddng phap van dap thddng ddpc sd dung phoi hdp vdi cac phddng phap khac nhim lam cho HS tich cdc, hdng thu va hpc tap hieu qua hon KHGD so 55, thdng - 2010 Khi soan cac cau hdi GV can Idu y cac yeu cau sau day: - Cau hdi phai cd npi dung chinh xac, ro rang, sat vdi muc dich, yeu cau cua bai hpc, khong lam cho ngddi hpc co the hieu theo nhieu each khac - Cau hdi phai sat vdi tdng loai ddi tdpng HS NghTa la phai cd nhieu cau hdi d cac mdc dp khac nhau, khong qua de va cung khong qua kho GV cd kinh nghiem thudng td cho HS thay cac cau hdi deu cd tarn quan va dp khd nhd (de HS yeu cd the tra Idi ddpc nhdng cau hdi vda sdc ma khong cd cam giac td ti ring minh ch? cd the tra Idi dddc nhdng cau hdi de va khong quan trong) - Cung mpt npi dung hpc tap, vdi cung mpt muc dich nhd nhau, GV cd the sd dung nhieu dang cau hdi vdi nhieu hinh thdc hdi khac Ben canh nhdng cau hdi chinh can chuan bi nhdng cau hdi phu (tren cd sd dd kien cac cau tra Idi cua HS, dd cd the co nhdng cau tra Idi sai) de tinh hinh thdc te ma gdi y, dan dit tiep Xet chat Idpng cau hdi ve mat yeu cau nang Idc nhan thdc, ngddi ta cd the phan biet hai loai chinh 1.5.1 Loai cau hoi cd yeu cau thap, doi hdi kha nang tai hien kien thdc, nhd lai va trinh bay lai dieu da hpc : "nhan dang" cac khai niem, dinh li, quy tie "Nhan dang mpt khai niem" la phat hien xem mpt ddi tddng cho trddc cd cac dac trdng cua mpt khai niem nao dd hay khong "Nhan dang mpt dinh li" la phat hien xem mpt tinh hudng cho trddc cd an khdp vdi mpt d|nh li nao dd hay khong Loai cau hdi dddc sd dung HS sip ddpc gidi thieu tai lieu mdi, dang luyen tap, thdc hanh, dang on tap nhdng dieu da hpc Vi du: The nao la hai phddng trinh tddng dddng? Cho vi du (tai hien kien thdc) Trinh bay cac bddc giai bai toan bing each lap phddng trinh (trinh bay lai dieu da hoc) Trong cac ham so sau ham so nao la ham so bac nhat ? a) y b)y 5x c)y d)y V3(x V5 JX 17 Khoa hoc Gido due- Nghien cuiu (cau hoi nham nhan dang khai niem ham so bac nhat) Khong giai phuong trinh hay tinh tdng va tich cac nghiem so cua cac phuong trinh bac hai sau: a)x ? 5x< 15-0: b) x xV3-V5=0 Oe tra Idi cau hdi nay, HS phai nhan dang dinh li Vi -et PhUdng trinh d cau a) cd A= (-5) - 15 < nen phddng trinh vo nghiem ? Phuong trinh d cau b) cd A = (-V3 f - ( - V ) = + \/5 > nen cd the ap dung dinh li Vi - et de tinh tdng va tich cac nghiem: x, + x = - = V3 ; x,x = - = - V5 ? a Loai cau hdi yeu cau thap thddng danh cho HS trung binh trd xudng 1.5.2 Loai cau hdi cd yeu cau cao ddi hdi sd thdng hieu, kT nang phan tich, tdng hdp, so sanh , the hien dddc cac khai niem, dinh li Loai cau hdi thddng dddc sd dung HS da cd kien thdc cO ban, GV mudn HS sd dung kien thdc ay tinh hudng mdi cd the phdc tap hdn HS dang tham gia giai quyet van de: mudn danh gia nang Idc sang tao cua HS Vi du: a) Cho vi du ve: mot phddng trinh bac hai cd hai nghiem phan biet: mot phddng trinh bac hai cd nghiem kep b) Cho vi du ve mpt phddng trinh bac hai cd hai nghiem phan biet deu dddng (HS phai hieu dinh li Vi- et) * Vi du minh hoa Vi du Khi luyen tap ve he thdc ve canh va dddng cao tarn giac vuong (Hinh hpc Idp 9) cd the yeu cau HS tinh x, y hinh ve ben 18 Khi hddng dan HS giai bai toan cd the sd dung he thdng cau hdi sau: - Bai toan da cho nhdng yeu to gi? Can xac dinh yeu to nao? - Nen tinh dai Idpng nao trddc, vi sao? - Tinh ddpc y bang each nao? Sd dung he thdc nao? - Tinh ddpc x bang each nao? Sd dung he thdc nao? - Cd each nao khac de tinh x? Vi du Khi day ve thi ham sd bac nhat, d bddc cung cd cd the yeu cau HS tra Idi cac cau hdi sau day: a) Cho ba vi du ve ham so bac nhat ma dd thi cua chung doi mpt cat b) Cho ba vi du ve ham so bac nhat ma thi cua chung d t tai diem cd tung dp bang Oe tra Idi ddpc nhdng cau hdi nay, HS can van dung kien thdc ve thi cua ham so bac nhat: Cau a) chi can cho ba ham so dang y = ax + b nhdng cd he so a khac Cau b) can cho ham so dang y = ax + b nhdng cd he so a khac va he so b = 2, ching han y = x + 2;y = - x + 2;y = x + de cho thi cua chung deu cat true tung tai diem cd tung dp bang 2 Phddng phap day hoc phat hien va giai quyet van de 2.1 Ban chat Day hpc phat hien va giai quyet van de (PH & GQVO) la PPDH dd GV tao nhdng tinh hudng cd van de, dieu khien HS phat hien van de, hoat dpng td giac, tich cdc, chu dpng, sang tao de giai quyet van de va thdng qua dd chiem ITnh tri thdc, ren luyen kT nang va dat dddc nhdng muc dich hpc tap khac Dac trdng cd ban cua day hpc PH & GQVO la "tinh hudng gpi van de" vi "Td chi bat dau xuat hien tinh hudng cd van de" (Rubinstein) Tinh hudng cd van de (tinh hudng gpi van de) la mpt tinh hudng gpi cho HS nhdng khd khan ve If luan hay thdc tien ma hp thay can va cd kha nang vdpt qua, nhdng khdng phai tdc khic bing mpt thuat giai, ma phai trai qua qua trinh tich cdc suy nghT, hoat dpng de bien ddi ddi tddng hoat dpng hoac dieu chinh kien thdc sin cd 2.2 Quy trinh thuc hien Bddc Phat hien hoac tham nhap van de - Phat hien van de td mpt tinh hudng gpi KHGD so 55, thdng - 2010 ghien cdu van de - Giai thich va chinh xac hoa tinh hudng (khi can thiet) de hieu dung van de dddc dat - Phat bieu van de va dat muc tieu giai quyet van de dd Bddc Tim giai phap: Tim each giai quyet van de : + Phan tich van de: lam ro mdi lien he gida cai da biet va cai can tim (dda vao nhdng tri thdc toan da hpc, lien tddng tdi nhdng dinh nghTa va dinh li thich hdp) + Hddng dan HS tim chien Idpc GQVO thong qua de xuat va thdc hien hddng giai quyet van de Can thu thap, td chdc dd lieu, huy dpng tri thdc; sd dung nhdng phddng phap, kT thuat nhan thdc, tim doan suy luan nhd hddng dich, quy la ve quen, dac biet hoa, chuyen qua nhdng trddng hdp suy bien, tddng td hoa, khai quat hoa, xem xet nhdng mdi lien he va phu thupc, suy xuoi, suy ngdpc tien, suy ngddc lui, Phddng hddng de xuat cd the dddc dieu chinh can thiet Ket qua cua viec de xuat va thdc hien hddng giai quyet van de la hinh dddc mpt giai phap + Kiem tra tinh dung dan cua giai phap: neu giai phap dung thi ket thuc ngay, neu khong dung thi lap lai td khau phan tich van de cho den tim dddc giai phap dung Sau da tim mpt giai phap, cd the tiep tuc tim them nhdng giai phap khac, so sanh chung vdi de tim giai phap hdp li nhat Bddc Trinh bay giai phap: HS trinh bay lai toan bp td viec phat bieu van de cho tdi giai phap Neu van de la mpt de bai cho san thi co the khdng can phat bieu lai van de Bddc Nghien cdu sau giai phap - Tim hieu nhdng kha nang dng dung ket qua - Oe xuat nhdng van de mdi cd lien quan nhd xet tddng td, khai quat hoa, lat ngddc van de, va giai quyet neu cd the 2.3 Uu diem - Phddng phap gdp phan tich cdc vao viec ren luyen td phe phan, td sang tao cho HS Tren co sd sd dung vdn kien thdc va kinh nghiem da cd HS se xem xet, danh gia, thay ddpc vain de can giai quyet - Day la phddng phap phat then ddpc kha nang tim toi, xem xet van de dddi nhieu gdc khac Trong PH & GQVO, HS se huy dong ddpc tri thdc va kha nang ca nhan, kha KHGD so 55, thdng - 2010 • Khoa hoc Gido due narig hpp tac, "trao ddi, thao luan vdi ban be de tim each giai quyet tot nhat - Thong qua viec giai quyet van de, HS dddc ITnh hpi tri thdc, kT nang va phddng phap nhan thdc ("giai quyet van de" khdng chi thupc pham tru phdOng phap ma da trd mpt muc dich day hpc, dddc cu the hoa mpt muc tieu la phat then nang Idc giai quyet van de, mpt nang Idc cd vi tri hang dau de ngddi thich dng dddc vdi sd phat then cua xa hpi) 2.4 Han che - PhdOng phap doi hdi ngddi GV phai dau td nhieu thdi gian va cdng sdc; GV phai cd nang Idc sd pham tot mdi suy nghT de tao ddoc nhieu tinh hudng gdi van de va hddng dan HS tim toi de PH & GQVO - Viec td chdc tiet hpc hoac mpt phan cua tiet hpc theo phdOng phap PH & GQVO doi hdi phai cd nhieu thdi gian hdn so vdi binh thddng Hdn nda, Lecne da cho rang: chi cd mpt so tri thdc va phddng phap hoat dpng nhat d|nh, dddc Ida chpn kheo leo va cd cO sd mdi trd ddi tdpng cua day hpc PH & GQVO 2.5 Mot so lull y Lecne da cho rang: so tri thdc va kT nang ddpc HS thu Idpm qua trinh day hpc PH & GQVO se giup hinh nhdng cau true dac biet cua td Nhd nhdng tri thdc dd, tat ca nhdng tri thdc khac ma HS da ITnh hpi khdng phai trdc tiep bang nhdng phddng phap day hpc PH & GQVO, se dddc chu the chinh ddn lai, cau true lai Do dd, khdng nen yeu cau HS td kham pha tat cac cac tri thdc qui dinh chddng trinh - Cho HS PH & GQVO ddi vdi mpt bp phan npi dung hpc tap, cd the cd sd giup dd cua GV vdi mdc dp nhieu it khac HS ddpc hpc khdng chi ket qua ma dieu quan hdn la ca qua trinh PH & GQVO - HS chinh ddn lai, cau true lai each nhin ddi vdi bp phan tri thdc lai ma hp da ITnh hpi khong phai bang dddng td PH & GQVD, tham chi cd the cung khdng phai nghe GV thuyet trinh PH & GQVO Ti cac van de ngddi hpc PH & GQVO so vdi chddng trinh thupc vao dac diem cua mon hpc, vao ddi tdpng HS va hoan canh cu the Tuy nhien, phddng hddng chung la: ti phan npi dung ddpc day theo each de HS PH & GQVO khong choan het toan bp mon hpc nhdng cung phai du de ngddi hpc biet each thdc, cd kT nang giai quyet van de va 19 Khoa hoc Gido dueco kha nang cau true lai tri thdc, biet nhin toan bo noi dung lai dudi dang dang qua trinh hinh va phat then theo each PH & GQVD - GV can hieu dung cac each tao tinh hudng gpi van de va tan dung cac co hpi de tao tinh hudng dd, ddng thdi tao dieu kien de HS td Idc giai quyet van de Day hpc PH & GQVD cd the ap dung cac giai doan cua qua trinh day hpc: hinh kien thdc mdi, cung cd kien thdc va kT nang, van dung kien thdc Phddng phap can hddng tdi mpi ddi tdpng HS chd khdng chi ap dung rieng che HS kha gidi Mpt so each thong dung de tao tinh hudng gpi van de la: Dd doan nhd nhan xet trdc quan, thdc hanh hoac hoat dpng thdc tien; Lat ngdpc van de; Xet tddng td; Khai quat hoa; Khai thac kien thdc cu, dat van de dan den kien thdc mdi; Giai bai tap ma chda biet thuat giai trdc tiep; Tim sai lam Idi giai; Phat hien nguyen nhan sai lam va sda chda sai lam 2.6 Sau day la mpt sd vi du ve cac each tao tinh hudng cd van de De thdc hien day hoc phat hien va giai quyet van de, diem xuat phat la tao tinh hudng cd van de Sau day la mot so each thdng dung de tao tinh hudng cd van de Cach 1: Dd doan nhd nhan xet fait quan, nhd thdc hanh hoac hoat dpng thdc tien HS quan sat (cd the hoat dpng gdc, canh, gap hinh ) mot so cac tarn giac co kich thddc, hinh dang khac va tim dac diem chung cua chung Cau tra Idi cua HS cd the la: cd ba canh, cd ba gdc Cho HS td thao luan, cung vdi sd dan dat cua GV di den dd doan: cac tarn giac tren cd tdng ba gdc bang 1800 Cach 2: Lat ngddc van de Oat van de nghien cdu menh de dao sau chdng minh mpt tinh chat, mpt dinh li Vi du: sau HS da hpc dinh li Pitago: "Trong mpt tarn giac vuong, binh phddng mpt canh huyen bang tdng binh phddng cua hai canh gdc vuong", cd the lat ngddc van de: Neu mpt tarn giac ma cd binh phddng mpt canh bang tdng binh phddng hai canh gdc vuong thi tarn 20 Nghien cUtl giac dd co phai la tarn giac vuong khong Cach 3: Xem xet tddng td Xet nhdng phep tddng td theo nghTa la chuyen td mpt trddng hpp rieng sang mpt trddng hpp rieng khac cua cung mpt cai tdng quat Vi du: Cho a + b = 2, chdng minh a + b >2 Sau chdng minh ddpc, HS cd the neu len cac bai toan tddng td nhd: Cho a + b = 2, tim gia tri nhd nhat cua a' + b hoac cho a + b + c = 3, chdng minh a' + b + c > 3; 2 2 Cach 4: Khai quat hoa Vi du: td a - b2 = (a - b) (a + b) a - b = (a - b) (a + ab + b ) cd the dd doan a - b" = ? (n N; n > 2) Cach 5: Khai thac kien thdc cu dat van de dan den kien thdc mdi Vi du: Sau hpc cong thdc nghiem cua phddng trinh bac hai, cd the yeu cau mdi HS td lay vi du ve phdOng trinh bac hai cd hai nghiem; sau dd yeu cau cac em giai de tim cac nghiem dd rdi tinh tdng cac nghiem, tich cac nghiem Trong luc dd, GV goi mpt HS khac len bang viet cdng thdc nghiem cua phddng trinh bac hai rdi tinh tdng va tich cua hai nghiem dd Td cac ket qua thu dddc, dat van de: vay cd mdi lien he nao gida tdng va tich cac nghiem cua phddng trinh bac hai vdi cac he so cua phddng trinh dd, tddd dan den kien thdc mdi "Dinh li Vi-et" Trong day hpc mdn Toan, cac cO hpi nhd vay rat nhieu, dd PPDH PH & GQVO cd kha nang ddpc ap dung rpng rai day hpc nham phat huy tinh chu dpng, sang tao cua HS * Vi du minh hoa Vi du Day dinh li ve tdng cac gdc cua mpt td giac: Bddc Phat hien hoac tham nhap van de: Mpt tarn giac bat ki deu cd tdng cac gdc bang 1800 Bay gid cho mpt td giac bat ky, ching han ABCD, lieu ta co the ndi gi ve tdng cac gdc cua nd? Lieu tdng cac gdc cua nd cd phai la mpt hlng so tddng td nhd trddng hpp tarn giac hay khong? (6 day da sddung each "Khai thac kien thdc cu dat van de din den kien thdc mdi" de tao tinh hudng cd van de) Bddc Tim giai phap: GV gdi y cho HS "quy la ve quen", dda viec xet td giac ve viec xet tarn giac bing each tao nen nhdng tarn giac tren 3 2 n KHGD so 55, thdng - 2010 Nghien curu hinh ve tuong dng vdi de bai Tddd dan den viec ke dddng cheo AC cua td giac ABCD, td dd HS tim each giai quyet van de da dat Bddc Trinh bay giai phap: HS trinh bay lai qua trinh giai quyet bai toan: td viec ve hinh ghi gia thiet ket luan den viec chdng minh Bddc Nghien cdu sau giai phap: Nghien cdu trddng hop dac biet td giac cd gdc bang thi mdi gdc deu la gdc vuong PhdOng phap day hoc hdp tac nhdm nhd 3.1 Ban chat Day la mot PPDH ma "HS dddc phan chia tdng nhdm nhd rieng biet, chiu trach nhiem ve mpt muc tieu nhat, ddpc thdc hien thdng qua nhiem vu rieng biet cua tdng ngddi Cac hoat dpng ca nhan rieng biet ddpc td chdc lai, lien ket hdu cd vdi nham thdc hien mpt muc tieu chung" 3.2 Quy trinh thuc hien Bddc 1: Lam viec chung ca Idp: - Neu van de, xac dinh nhiem vu nhan thdc: - To chdc cac nhdm, giao nhiem vu cho cac nhdm; - Hddng dan each lam viec theo nhdm Bddc 2: Lam viec theo nhdm - Phan cdng nhdm, tdng ca nhan lam viec dpc lap; - Trao ddi y kien, thao luan nhdm; - Cd dai dien trinh bay ket qua lam viec cua nhdm Bddc 3: Thao luan, tdng ket trddc toan Idp - Cac nhdm lan Idpt bao cao ket qua; - Thao luan chung - GV tdng ket, dat van de cho bai tiep theo hoac van de tiep theo 3.3 l/u diem - HS dddc hpc each cpng tac tren nhieu phdOng dien - HS dddc neu quan diem cua minh, ddpc nghe quan diem cua ban khac nhdm, Idp; ddpc trao ddi, ban luan ve cac y kien khac va dda Idi giai tdi du cho nhiem vu ddpc giao cho nhdm Qua dd, td phe phan, kT nang lam viec hdp tac cua HS dddc ren luyen va phat then - Cac vien nhdm chia se cac suy nghT, ban khoan, kinh nghiem, hieu biet cua ban than, cung xay ddng nhan thdc, thai dp mdi va hpc hdi lan - HS de hieu, de nhd hon vi hp dddc tham gia trao ddi, trinh bay van de neu HS hao hdng cd sd ddng gdp cua minh vao cong chung cua ca Idp KHGD so 55, thdng - 2010 •Khoa hoc Gido due 3.4 Han che Viec ap dung phddng phap day hpc hdp tac nhdm nhd thddng b| han che bdi: - Khong gian chat hep cua tdng Idp hpc va thdi gian han dinh cua tiet hpc - Tinh than tham gia cua cac vien nhdm: neu khong phan cong hpp li, chi cd mpt vai HS hoc kha tham gia da so HS khac khong hoat dpng 3.5 Mot sd luu y Chi nhdng hoat dpng doi hdi sd phoi hpp cua cac ca nhan de nhiem vu hoan nhanh chdng hdn, hieu qua hdn hoat dpng ca nhan mdi nen sd dung phddng phap Ching han cac bai tap cd nhieu phan cd the phan nhdm de cac em phan cong giai quyet hoac thdc hien mot so tro chdi toan hoc Tao dieu kien de cac nhom td danh gia lan hoac ca Idp cung danh gia Khdng nen lam dung hoat dpng nhdm va can de phong xu hddng hinh thdc (tranh Idi suy nghT: ddi mdi PPDH la phai sd dung hoat dpng nhdm) Tuy theo tdng nhiem vu hpc tap ma sd dung hinh thdc HS lam viec ca nhan hoac hoat dpng nhdm cho phu hpp * Vi du minh hoa Vi du Khi day bai "Lfdc va bpi" d Idp 6, sau hpc xong dinh nghTa va each tim ddc va bpi cua mot so, de cung cd GV cd the thdc hien hoat dpng nhdm : Chia Idp cac nhdm td den HS Cac nhdm cd so thd td le giai bai d phieu so 1, nhdm cd so thd td chin giai bai d phieu so Thdi gian lam viec nhdm la phut Phieu so Cho cac sd: 1; 12; 14; 2; 18; 23; 0; 3; a) Viet tap hdp A cac so thupc day tren la boi cua b) Viet tap hdp B cac so thupc day tren la ddc cua Phieu so Cho mn = 30 va x = 7t (m, n, x, t ? N*) Hay dien vao cho trdng cac td "ddc", "bpi" de dddc cac ket luan dung a/ m la cua 30 b/ 30 la cua m c/ x la cua t d/ x la cua 7t e/1 la cua x g/ la cua x Sau thdc hien xong hoat dong tren, GV cd the td chdc tro chdi: "Thi nhdm nao nhanh hdn" bang each chia Idp cac nhdm moi nhdm HS de giai bai: 21 Khoa hoc Gido due- ghien cut "77m cac bdi cua Idn hdn 20 va nho hdn 200 " Sau khoang phut, gpi dai dien ba nhom co ket qua nhanh nhat len ghi ket qua len bang Danh gia ket qua cua cac nhdm theo so Iddng so ma cac nhdm da viet dung Sau dd yeu cau cac nhdm ddi cheo bang phu hay phieu hpc tap de HS nhan xet, danh gia lan Vi du Khi day bai Oinh li Pitago d Idp 7, de HS tiep can vdi dinh li, GV cd the chia Idp cac nhdm, giao cho mdi nhdm mpt bang phu vdi yeu cau: 1) Ve va cac canh lai cua tarn giac rdi ghi ket qua vao bang (Moi nhdm cd mpt bang phu, dd GV da ve sin cac tarn giac vuong cd hai kich thddc cho trddc) Day la vi du bang phu cho nhdm - HS va ghi vao bang 1: canh gdc canh gdc canh gdc vuong vuong vuong cm cm A ABC A DEF cm cm A IGH cm 15 cm Vdi nhdm 2, GV cho cac hinh tddng td va yeu cau HS dien vao bang 2: A ABC A DEF A IGH canh gdc vuong cm cm cm canh gdc vuong canh huyen 12 cm 12 cm Tddng td cd cac bang cho nhdm 3, Sau va dien vao bang xong, GV yeu cau cac nhdm thdc hien yeu cau tiep theo: 2) Gpi cac canh gdc vuong dd lan Idpt la a, b, canh huyen la c Hay so sanh c' va a + b Td ket qua lam viec cua cac nhdm, HS thay ddpc mdi quan he gida c' va a' + W tarn giac vuong, td dd GV gidi thieu npi dung dinh li Vdi each lam nhd vay, cac nhdm HS td minh dac, tinh toan, so sanh de rut ket luan Khi 22 ? doi chieu chung ket qua cua ca Idp, HS se cd ddpc so cac canh cua nhieu tarn giac khac nhau, tinh thuyet phuc cua dinh li se cao hdn (ddi vdi HS Idp cac em chda dddc chdng minh dinh li mpt each chat che) Ket luan Trong qua trinh ddi mdi PPDH, GV phai the hien bai soan y thdc tao mdi quan he hpp li gida day kien thdc va day kT nang vdi day phddng phap suy nghT va hanh dpng Ddi vdi mdn Toan, can cd quan diem la td quan hon kien thdc, nim vdng phddng phap quan hon thupc li thuyet Day toan la day suy nghT, day bp dc cua HS thao cac thao tac td duy: phan tich, tdng hpp, trdu tdpng hoa, dac biet hoa, tddng td dd phan tich, tdng hdp la nen tang Phai cung cap cho HS nhdng tri thdc ve phddng phap de HS cd the td minh tim toi, td minh phat hien va phat then van de, dd doan dddc ket qua, tim dddc hddng giai cua mpt bai toan, hddng chdng minh mpt dinh li, giup HS hieu ban chat sau sic mpt khai niem, cac menh de, y nghTa va npi dung cua cac cong thdc, chdng minh, td dd ma nhd lau cac kien thdc toan hpc va neu quen cd the td minh tim lai dddc GV khdng ddng vai tro don thuan la ngddi truyen dat kien thdc GV trd ngddi thiet ke, td chdc hddng dan cac hoat dpng - dpc lap hoac theo nhdm nhd- de HS td idc chiem ITnh cac kien thdc mdi, hinh cac kT nang, thai dp mdi theo yeu clu cua chddng trinh Tren Idp, HS hoat dong la chinh, nhdng trddc dd soan bai, GV phai dau td nhieu cdng sdc va thdi gian mdi cd the thdc hien bai len Idp vdi vai tro la ngddi gpi md, xuc tac, dpng vien, td van, tai cac hoat dpng tim toi, tranh luan cua HS GV phai phoi hop cac PPDH de phat huy ddpc tinh tich cdc cua HS, lam cho cac em tiep thu kien thdc mpt each vdng chic va hieu qua TAl LIEU THAM KHAO J B Baron, R J Sternberg, Day ki nang tu duy, va thuc tien, Dd an Viet - Bi,2000 Nguyen Ba Kim, Phuong phap day hoc mon Toan, N Dai hoc Su pham, 2002 Ton Than, Phan Thi Luyen, Dang Thu Thuy, Doi mdi PPDH mdn Toan d trudng Trung hoc co so NXB due, 2008 la Leene, Day hoc nen van de, NXB Giao due, Ha N 1977 SUMMARY Based on the new guidance for teaching Mathematic in lower secondary schools the article discusses the cation of Mathematics teaching methods, including tion-answer, problem identification and solving, co tive learning in groups (by nature of the methods, p dures, pros and cons of the methods as well as hints KHGD so 55, thdng - 2010 ... nhan thdc: - To chdc cac nhdm, giao nhiem vu cho cac nhdm; - Hddng dan each lam viec theo nhdm Bddc 2: Lam viec theo nhdm - Phan cdng nhdm, tdng ca nhan lam viec dpc lap; - Trao ddi y kien, thao... nhdm lan Idpt bao cao ket qua; - Thao luan chung - GV tdng ket, dat van de cho bai tiep theo hoac van de tiep theo 3.3 l/u diem - HS dddc hpc each cpng tac tren nhieu phdOng dien - HS dddc neu quan... ke, td chdc hddng dan cac hoat dpng - dpc lap hoac theo nhdm nhd- de HS td idc chiem ITnh cac kien thdc mdi, hinh cac kT nang, thai dp mdi theo yeu clu cua chddng trinh Tren Idp, HS hoat dong