SGV TOAN 4

["","","","","","","","","","","","","","","","","","","","","","","","","B\u00e0i 5: \u2013 HS xa\u0301c \u0111i\u0323nh ca\u0301i \u0111a\u0303 cho va\u0300 c\u00e2u ho\u0309i cu\u0309a ba\u0300i toa\u0301n, xa\u0301c \u0111i\u0323nh ca\u0301c vi\u00ea\u0323c c\u00e2\u0300n la\u0300m: Ch\u1ecdn s\u1ed1 thi\u0301ch h\u01a1\u0323p \u0111\u1ec3 thay v\u00e0o .?. \u2013 HS l\u00e0m b\u00e0i c\u00e1 nh\u00e2n. \u2013 S\u1eeda b\u00e0i, GV khuy\u1ebfn kh\u00edch nhi\u1ec1u nh\u00f3m tr\u00ecnh b\u00e0y b\u00e0i l\u00e0m (c\u00f3 gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m: t\u00ecm th\u1eeba s\u1ed1 ch\u01b0a bi\u1ebft, s\u1ed1 chia, s\u1ed1 b\u1ecb chia th\u00f4ng qua c\u00e1c th\u00e0nh ph\u1ea7n \u0111\u00e3 bi\u1ebft). V\u00ed d\u1ee5: l\u1ea5y t\u00edch (900) chia cho th\u1eeba s\u1ed1 \u0111\u00e3 bi\u1ebft (30) ta t\u00ecm \u0111\u01b0\u1ee3c th\u1eeba s\u1ed1 kia (30). N\u1ebfu HS qu\u00ean quy t\u1eafc, GV h\u01b0\u1edbng d\u1eabn HS d\u00f9ng m\u1ed9t ph\u00e9p t\u00ednh \u0111\u01a1n gi\u1ea3n \u0111\u1ec3 nh\u1edb l\u1ea1i c\u00e1ch l\u00e0m. V\u00ed d\u1ee5: 3 \u00d7 9 = 27\t 3 \u00d7 9 = 27 27 : 9 = 3\t 27 : 3 = 9 ... IV. V\u1eadn d\u1ee5ng, tr\u1ea3i nghi\u1ec7m B\u00e0i 6: \u2013 T\u00ecm hi\u1ec3u b\u00e0i: + \u0110\u1ecdc k\u0129 \u0111\u1ec1 b\u00e0i. + Xa\u0301c \u0111i\u0323nh ca\u0301i \u0111a\u0303 cho va\u0300 c\u00e2u ho\u0309i cu\u0309a ba\u0300i toa\u0301n. \u2013 HS (nh\u00f3m \u0111\u00f4i) th\u1ea3o lu\u1eadn, t\u00ecm c\u00e1ch gi\u1ea3i quy\u1ebft. + Mu\u1ed1n bi\u1ebft s\u1ed1 m\u00e9t v\u1ea3i trung b\u00ecnh 1 ng\u00e0y t\u1ed5 M\u1ed9t c\u1eaft may \u00edt h\u01a1n t\u1ed5 Hai \u2192 Ph\u1ea3i bi\u1ebft s\u1ed1 m\u00e9t v\u1ea3i trung b\u00ecnh 1 ng\u00e0y m\u1ed7i t\u1ed5 c\u1eaft may. + Mu\u1ed1n bi\u1ebft s\u1ed1 m\u00e9t v\u1ea3i trung b\u00ecnh 1 ng\u00e0y m\u1ed7i t\u1ed5 c\u1eaft may \u2192 Ph\u1ea3i bi\u1ebft t\u1ed5ng s\u1ed1 m\u00e9t v\u1ea3i v\u00e0 s\u1ed1 ng\u00e0y c\u1eaft may h\u1ebft s\u1ed1 v\u1ea3i \u0111\u00f3 c\u1ee7a m\u1ed7i t\u1ed5. \u2013 HS tr\u00ecnh b\u00e0y b\u00e0i c\u00e1 nh\u00e2n. B\u00e0i gi\u1ea3i 1 500 : 30 = 50 Trung b\u00ecnh 1 ng\u00e0y t\u1ed5 M\u1ed9t c\u1eaft may h\u1ebft 50 m v\u1ea3i. 1 500 : 25 = 60 Trung b\u00ecnh 1 ng\u00e0y t\u1ed5 Hai c\u1eaft may h\u1ebft 60 m v\u1ea3i. 60 \u2013 50 = 10 Trung b\u00ecnh 1 ng\u00e0y t\u1ed5 M\u1ed9t c\u1eaft may \u00edt h\u01a1n t\u1ed5 Hai 10 m v\u1ea3i. \u2013 S\u1eeda b\u00e0i, GV khuy\u1ebfn kh\u00edch HS tr\u00ecnh b\u00e0y b\u00e0i l\u00e0m. \u2026 224","B\u00e0i 54. H\u00ccNH B\u00ccNH H\u00c0NH (2 ti\u1ebft) A. Y\u00eau c\u1ea7u c\u1ea7n \u0111\u1ea1t \u2013 HS nh\u1eadn bi\u1ebft \u0111\u01b0\u1ee3c h\u00ecnh b\u00ecnh h\u00e0nh v\u00e0 t\u00ednh ch\u1ea5t v\u1ec1 c\u1ea1nh c\u1ee7a h\u00ecnh b\u00ecnh h\u00e0nh; v\u1ebd \u0111\u01b0\u1ee3c h\u00ecnh b\u00ecnh h\u00e0nh tr\u00ean gi\u1ea5y k\u1ebb \u00f4 vu\u00f4ng. \u2013 V\u1eadn d\u1ee5ng gi\u1ea3i quy\u1ebft c\u00e1c v\u1ea5n \u0111\u1ec1 \u0111\u01a1n gi\u1ea3n li\u00ean quan \u0111\u1ebfn h\u00ecnh b\u00ecnh h\u00e0nh. \u2013 HS c\u00f3 c\u01a1 h\u1ed9i \u0111\u1ec3 ph\u00e1t tri\u1ec3n c\u00e1c n\u0103ng l\u1ef1c t\u01b0 duy v\u00e0 l\u1eadp lu\u1eadn to\u00e1n h\u1ecdc; giao ti\u1ebfp to\u00e1n h\u1ecdc; m\u00f4 hi\u0300nh ho\u00e1 toa\u0301n ho\u0323c; s\u1eed d\u1ee5ng c\u00f4ng c\u1ee5, ph\u01b0\u01a1ng ti\u1ec7n h\u1ecdc to\u00e1n; gi\u1ea3i quy\u1ebft v\u1ea5n \u0111\u1ec1 to\u00e1n h\u1ecdc v\u00e0 c\u00e1c ph\u1ea9m ch\u1ea5t nh\u00e2n \u00e1i, tr\u00e1ch nhi\u1ec7m, ch\u0103m ch\u1ec9. B. \u0110\u1ed3 d\u00f9ng d\u1ea1y h\u1ecdc GV: Th\u01b0\u1edbc th\u1eb3ng, b\u1ed9 x\u1ebfp h\u00ecnh, c\u00e1c h\u00ecnh \u1ea3nh c\u00f3 trong b\u00e0i (n\u1ebfu c\u1ea7n). HS: Th\u01b0\u1edbc th\u1eb3ng, gi\u1ea5y k\u1ebb \u00f4 vu\u00f4ng, b\u1ed9 x\u1ebfp h\u00ecnh. C. C\u00e1c ho\u1ea1t \u0111\u1ed9ng d\u1ea1y h\u1ecdc ch\u1ee7 y\u1ebfu I. Kh\u1edfi \u0111\u1ed9ng \u2013 HS quan s\u00e1t m\u1eb7t c\u1ee7a to\u00e0 nh\u00e0 \u2192 Nh\u1eadn bi\u1ebft s\u1ef1 \u0111\u1eb7c bi\u1ec7t v\u1ec1 h\u00ecnh d\u1ea1ng m\u1eb7t c\u1ee7a to\u00e0 nh\u00e0. Ch\u1eb3ng h\u1ea1n: + C\u00e1c to\u00e0 nh\u00e0 kh\u00e1c th\u01b0\u1eddng c\u00f3 m\u1eb7t ti\u1ec1n l\u00e0 h\u00ecnh ch\u1eef nh\u1eadt. + H\u00ecnh n\u00e0y v\u1eeba gi\u1ed1ng v\u1eeba kh\u00f4ng gi\u1ed1ng h\u00ecnh ch\u1eef nh\u1eadt. \u2026 \u2013 GV gi\u1edbi thi\u1ec7u: M\u1eb7t c\u1ee7a to\u00e0 nh\u00e0 m\u00e0 ch\u00fang ta \u0111ang quan s\u00e1t l\u00e0 h\u00ecnh b\u00ecnh h\u00e0nh \u2192 GV gi\u1edbi thi\u1ec7u v\u00e0o b\u00e0i. II. Kh\u00e1m ph\u00e1, h\u00ecnh th\u00e0nh ki\u1ebfn th\u1ee9c m\u1edbi: H\u00ecnh b\u00ecnh h\u00e0nh 1. Gi\u1edbi thi\u1ec7u h\u00ecnh b\u00ecnh h\u00e0nh \u2013 GV v\u1ebd h\u00ecnh b\u00ecnh h\u00e0nh ABCD tr\u00ean b\u1ea3ng l\u1edbp (n\u1ec1n l\u00e0 l\u01b0\u1edbi \u00f4 vu\u00f4ng) \u2192 GV ch\u1ec9 tay v\u00e0o h\u00ecnh v\u00e0 gi\u1edbi thi\u1ec7u: \u0110\u00e2y l\u00e0 h\u00ecnh b\u00ecnh h\u00e0nh ABCD \u2192 HS nh\u00ecn h\u00ecnh tr\u00ean b\u1ea3ng l\u1edbp v\u00e0 n\u00f3i theo \u2192 Nh\u00f3m hai HS ch\u1ec9 tay v\u00e0o h\u00ecnh trong SGK v\u00e0 n\u00f3i: H\u00ecnh b\u00ecnh h\u00e0nh ABCD. (L\u01b0u \u00fd: HS c\u00f3 th\u1ec3 \u0111\u1ecdc t\u1eeb b\u1ea5t k\u00ec \u0111\u1ec9nh n\u00e0o v\u00e0 theo chi\u1ec1u kim \u0111\u1ed3ng h\u1ed3 ho\u1eb7c ng\u01b0\u1ee3c chi\u1ec1u kim \u0111\u1ed3ng h\u1ed3 \u0111\u1ec1u \u0111\u01b0\u1ee3c, nh\u01b0ng ph\u1ea3i \u0111\u1ecdc tu\u1ea7n t\u1ef1 c\u00e1c \u0111\u1ec9nh. V\u00ed d\u1ee5: H\u00ecnh b\u00ecnh h\u00e0nh CDAB, \u2026) 2. Gi\u1edbi thi\u1ec7u t\u00ednh ch\u1ea5t v\u1ec1 c\u1ea1nh c\u1ee7a h\u00ecnh b\u00ecnh h\u00e0nh \u2013 HS n\u00eau s\u1ed1 c\u1ea1nh c\u1ee7a m\u1ed9t h\u00ecnh b\u00ecnh h\u00e0nh v\u00e0 k\u1ec3 t\u00ean c\u00e1c c\u1ea1nh c\u1ee7a h\u00ecnh b\u00ecnh h\u00e0nh ABCD. \u2013 GV gi\u1edbi thi\u1ec7u thu\u1eadt ng\u1eef c\u1ea1nh \u0111\u1ed1i di\u1ec7n, HS t\u1eadp s\u1eed d\u1ee5ng thu\u1eadt ng\u1eef n\u00e0y. (AB v\u00e0 DC l\u00e0 hai c\u1ea1nh \u0111\u1ed1i di\u1ec7n, AB v\u00e0 DC l\u00e0 m\u1ed9t c\u1eb7p c\u1ea1nh \u0111\u1ed1i di\u1ec7n; AD v\u00e0 BC l\u00e0 hai c\u1ea1nh \u0111\u1ed1i di\u1ec7n, AD v\u00e0 BC l\u00e0 m\u1ed9t c\u1eb7p c\u1ea1nh \u0111\u1ed1i di\u1ec7n.) \u2013 HS ho\u1ea1t \u0111\u1ed9ng theo nh\u00f3m b\u1ed1n: T\u00ecm hi\u1ec3u m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c c\u1ea1nh \u0111\u1ed1i di\u1ec7n c\u1ee7a h\u00ecnh b\u00ecnh h\u00e0nh ABCD. 225","C\u00e1c nh\u00f3m th\u1ea3o lu\u1eadn, tr\u00ecnh b\u00e0y v\u00e0 gi\u1ea3i th\u00edch nh\u1eadn x\u00e9t. (C\u00e1c c\u1ea1nh \u0111\u1ed1i di\u1ec7n b\u1eb1ng nhau: d\u1ef1a v\u00e0o s\u1ed1 \u00f4 vu\u00f4ng ho\u1eb7c d\u00f9ng th\u01b0\u1edbc \u0111o; c\u00e1c c\u1ea1nh \u0111\u1ed1i di\u1ec7n song song: nh\u1eadn bi\u1ebft qua tr\u1ef1c gi\u00e1c, kh\u00f4ng n\u00ean h\u1ecfi t\u1ea1i sao song song. N\u1ebfu c\u1ea7n, GV c\u00f3 th\u1ec3 gi\u1ea3i th\u00edch v\u1ec1 s\u1ef1 song song nh\u01b0 d\u01b0\u1edbi \u0111\u00e2y.) \u2013 GV h\u1ec7 th\u1ed1ng nh\u1eadn x\u00e9t c\u1ee7a c\u00e1c nh\u00f3m: + C\u1ea1nh AB song song v\u00e0 b\u1eb1ng c\u1ea1nh DC. + C\u1ea1nh AD song song v\u00e0 b\u1eb1ng c\u1ea1nh BC. \u2013 GV gi\u00fap HS kh\u00e1i qu\u00e1t ho\u00e1 t\u00ednh ch\u1ea5t c\u00e1c c\u1ea1nh \u0111\u1ed1i di\u1ec7n c\u1ee7a h\u00ecnh b\u00ecnh h\u00e0nh. GV h\u1ecfi \u0111\u1ec3 HS n\u00eau \u0111\u01b0\u1ee3c nh\u1eadn x\u00e9t: H\u00ecnh b\u00ecnh h\u00e0nh ABCD c\u00f3 hai c\u1eb7p c\u1ea1nh \u0111\u1ed1i di\u1ec7n song song v\u00e0 b\u1eb1ng nhau. \u2192 H\u00ecnh b\u00ecnh h\u00e0nh c\u00f3 hai c\u1eb7p c\u1ea1nh \u0111\u1ed1i di\u1ec7n song song v\u00e0 b\u1eb1ng nhau. L\u01b0u \u00fd: N\u1ebfu mu\u1ed1n gi\u1ea3i th\u00edch t\u1ea1i sao c\u00e1c c\u1ea1nh c\u1ee7a h\u00ecnh b\u00ecnh h\u00e0nh song song, c\u00f3 th\u1ec3 l\u00e0m nh\u01b0 sau: N\u1ebfu k\u00e9o c\u00e1c c\u1ea1nh c\u1ee7a h\u00ecnh b\u00ecnh h\u00e0nh ABCD, ta \u0111\u01b0\u1ee3c c\u00e1c c\u1eb7p \u0111\u01b0\u1eddng th\u1eb3ng kh\u00f4ng bao gi\u1edd c\u1eaft nhau, c\u00e1c c\u1eb7p \u0111\u01b0\u1eddng th\u1eb3ng \u0111\u00f3 song song v\u1edbi nhau. GV v\u1ebd tr\u00ean b\u1ea3ng l\u1edbp: AB DC (C\u1eb7p c\u1ea1nh AB v\u00e0 DC c\u00f3 th\u1ec3 d\u1ef1a v\u00e0o c\u00e1c d\u00f2ng k\u1ebb ngang.) III. Th\u1ef1c h\u00e0nh, luy\u1ec7n t\u1eadp 1. Th\u1ef1c h\u00e0nh Ba\u0300i 1: \u2013 HS (nh\u00f3m b\u1ed1n) nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u, th\u1ea3o lu\u1eadn, nh\u1eadn bi\u1ebft h\u00ecnh n\u00e0o l\u00e0 h\u00ecnh b\u00ecnh h\u00e0nh. \u2013 S\u1eeda b\u00e0i: + C\u00e1c nh\u00f3m tr\u00ecnh b\u00e0y: H\u00ecnh 1 v\u00e0 H\u00ecnh 4 l\u00e0 c\u00e1c h\u00ecnh b\u00ecnh h\u00e0nh (HS nh\u1eadn bi\u1ebft ch\u1ee7 y\u1ebfu qua tr\u1ef1c gi\u00e1c, GV kh\u00f4ng n\u00ean y\u00eau c\u1ea7u HS gi\u1ea3i th\u00edch). + Trong tr\u01b0\u1eddng h\u1ee3p HS l\u00e0m sai, v\u00ed d\u1ee5 c\u00e1c em n\u00f3i H\u00ecnh 2 c\u0169ng l\u00e0 h\u00ecnh b\u00ecnh h\u00e0nh \u2192 GV h\u01b0\u1edbng d\u1eabn HS d\u00f9ng hai c\u00e1i th\u01b0\u1edbc \u0111\u1eb7t v\u00e0o h\u00ecnh v\u1ebd nh\u01b0 d\u01b0\u1edbi \u0111\u00e2y \u2192 Hai c\u00e1i th\u01b0\u1edbc \u0111\u1ee5ng nhau \u2192 Hai c\u1ea1nh \u0111\u1ed1i di\u1ec7n n\u00e0y kh\u00f4ng song song \u2192 H\u00ecnh 2 kh\u00f4ng ph\u1ea3i h\u00ecnh b\u00ecnh h\u00e0nh. 226","Ba\u0300i 2: \u2013 HS (nh\u00f3m \u0111\u00f4i) nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u r\u1ed3i n\u00f3i cho nhau nghe (ch\u1ec9 tay v\u00e0o h\u00ecnh). \u2013 S\u1eeda b\u00e0i, GV l\u01b0u \u00fd HS n\u00f3i theo m\u1eabu c\u00e2u: V\u00ed d\u1ee5: a) H\u00ecnh b\u00ecnh h\u00e0nh KLMN c\u00f3 c\u00e1c c\u1eb7p c\u1ea1nh song song v\u00e0 b\u1eb1ng nhau l\u00e0: KL = NM = 2 m;\t\t\t KN = LM = 3 m. \u2026 Ba\u0300i 3: \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb nh\u00f3m b\u1ed1n. \u2013 S\u1eeda b\u00e0i, GV khuy\u1ebfn kh\u00edch c\u00e1c em n\u00f3i s\u1ef1 t\u01b0\u1edfng t\u01b0\u1ee3ng v\u1ec1 h\u00ecnh c\u1ee7a b\u1ea3n th\u00e2n. Ch\u1eb3ng h\u1ea1n: a) N\u1ebfu em l\u1ea5y tam gi\u00e1c b\u00ean tr\u00e1i \u0111\u1eb7t sang b\u00ean ph\u1ea3i th\u00ec c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c h\u00ecnh b\u00ecnh h\u00e0nh \u2192 Em mang sang b\u00ean ph\u1ea3i v\u00e0 t\u00ecm c\u00e1ch gh\u00e9p l\u1ea1i \u0111\u1ec3 \u0111\u01b0\u1ee3c h\u00ecnh b\u00ecnh h\u00e0nh. 2. Luy\u1ec7n t\u1eadp B\u00e0i 1: \u2013 HS (nh\u00f3m \u0111\u00f4i) nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u v\u00e0 th\u1ea3o lu\u1eadn. + Th\u1ee9 t\u1ef1 \u0111\u1ecdc c\u00e1c \u0111\u1ec9nh c\u1ee7a h\u00ecnh b\u00ecnh h\u00e0nh l\u00e0 ABCD \u2192 V\u1ecb tr\u00ed c\u1ee7a \u0111i\u1ec3m C kho\u1ea3ng ch\u1ed7 n\u00e0o? \u2192 V\u1ecb tr\u00ed n\u00e0y ph\u1ea3i tho\u1ea3 m\u00e3n \u0111\u1ec3 ABCD l\u00e0 h\u00ecnh b\u00ecnh h\u00e0nh. \u2013 HS l\u00e0m c\u00e1 nh\u00e2n (v\u1edf b\u00e0i t\u1eadp) r\u1ed3i chia s\u1ebb v\u1edbi b\u1ea1n. + V\u1ebd \u0111i\u1ec3m C. + V\u1ebd c\u00e1c \u0111o\u1ea1n th\u1eb3ng BC v\u00e0 DC. \u2013 Quan s\u00e1t h\u00ecnh v\u1eeba v\u1ebd xem c\u00f3 ph\u1ea3i h\u00ecnh b\u00ecnh h\u00e0nh ABCD. IV. V\u1eadn d\u1ee5ng, tr\u1ea3i nghi\u1ec7m B\u00e0i 2: \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb nh\u00f3m b\u1ed1n. \u2013 GV c\u00f3 th\u1ec3 g\u1ee3i \u00fd \u0111\u1ec3 HS l\u00e0m theo c\u00e1c b\u01b0\u1edbc: + V\u1ebd ch\u00ec tr\u00ean gi\u1ea5y k\u1ebb \u00f4 vu\u00f4ng. Ch\u1ea5m m\u1ed9t s\u1ed1 \u0111i\u1ec3m \u2192 D\u00f9ng th\u01b0\u1edbc th\u1eb3ng n\u1ed1i c\u00e1c \u0111i\u1ec3m (xem h\u00ecnh m\u1eabu) \u2192 Ch\u1ea5m ti\u1ebfp m\u1ed9t s\u1ed1 \u0111i\u1ec3m r\u1ed3i th\u1ef1c hi\u1ec7n nh\u01b0 tr\u00ean cho t\u1edbi khi \u0111\u01b0\u1ee3c to\u00e0n b\u1ed9 h\u00ecnh th\u1ee9 nh\u1ea5t (SGK). + T\u00f4 m\u00e0u theo m\u1eabu ho\u1eb7c theo \u00fd th\u00edch. \u2013 Tr\u01b0ng b\u00e0y s\u1ea3n ph\u1ea9m tr\u00ean b\u1ea3ng l\u1edbp. \u2013 Mang s\u1ea3n ph\u1ea9m v\u1ec1 nh\u00e0, treo \u1edf g\u00f3c h\u1ecdc t\u1eadp. Ho\u1ea1t \u0111\u1ed9ng th\u1ef1c t\u1ebf C\u00e1c nh\u00f3m nh\u1eadn ra c\u00e1c v\u1eadt c\u00f3 d\u1ea1ng h\u00ecnh b\u00ecnh h\u00e0nh: \u2013 Trong SGK. \u2013 Trong th\u1ef1c t\u1ebf. 227","B\u00e0i 55. H\u00ccNH THOI (2 ti\u1ebft) A. Y\u00eau c\u1ea7u c\u1ea7n \u0111\u1ea1t \u2013 HS nh\u1eadn bi\u1ebft \u0111\u01b0\u1ee3c h\u00ecnh thoi v\u00e0 t\u00ednh ch\u1ea5t v\u1ec1 c\u1ea1nh c\u1ee7a h\u00ecnh thoi; v\u1ebd \u0111\u01b0\u1ee3c h\u00ecnh thoi tr\u00ean gi\u1ea5y k\u1ebb \u00f4 vu\u00f4ng. \u2013 V\u1eadn d\u1ee5ng gi\u1ea3i quy\u1ebft c\u00e1c v\u1ea5n \u0111\u1ec1 \u0111\u01a1n gi\u1ea3n li\u00ean quan \u0111\u1ebfn h\u00ecnh thoi. \u2013 HS c\u00f3 c\u01a1 h\u1ed9i \u0111\u1ec3 ph\u00e1t tri\u1ec3n c\u00e1c n\u0103ng l\u1ef1c t\u01b0 duy v\u00e0 l\u1eadp lu\u1eadn to\u00e1n h\u1ecdc, giao ti\u1ebfp to\u00e1n h\u1ecdc, m\u00f4 hi\u0300nh ho\u00e1 toa\u0301n ho\u0323c, s\u1eed d\u1ee5ng c\u00f4ng c\u1ee5, ph\u01b0\u01a1ng ti\u1ec7n h\u1ecdc to\u00e1n, gi\u1ea3i quy\u1ebft v\u1ea5n \u0111\u1ec1 to\u00e1n h\u1ecdc v\u00e0 c\u00e1c ph\u1ea9m ch\u1ea5t nh\u00e2n \u00e1i, tr\u00e1ch nhi\u1ec7m, ch\u0103m ch\u1ec9. B. \u0110\u1ed3 d\u00f9ng d\u1ea1y h\u1ecdc GV: Th\u01b0\u1edbc th\u1eb3ng, b\u1ed9 x\u1ebfp h\u00ecnh, c\u00e1c h\u00ecnh \u1ea3nh c\u00f3 trong b\u00e0i (n\u1ebfu c\u1ea7n). HS: Th\u01b0\u1edbc th\u1eb3ng, gi\u1ea5y k\u1ebb \u00f4 vu\u00f4ng. C. C\u00e1c ho\u1ea1t \u0111\u1ed9ng d\u1ea1y h\u1ecdc ch\u1ee7 y\u1ebfu I. Kh\u1edfi \u0111\u1ed9ng \u2013 HS quan s\u00e1t c\u00e1c \u00f4 c\u1eeda k\u00ednh \u2192 Nh\u1eadn th\u1ea5y c\u00e1c \u00f4 k\u00ednh \u0111\u1eb9p (kh\u00f4ng ch\u1ec9 v\u00ec m\u00e0u s\u1eafc) \u2192 GV gi\u1edbi thi\u1ec7u: C\u00e1c \u00f4 c\u1eeda k\u00ednh c\u00f3 d\u1ea1ng h\u00ecnh thoi \u2192 GV gi\u1edbi thi\u1ec7u v\u00e0o b\u00e0i. II. Kh\u00e1m ph\u00e1, h\u00ecnh th\u00e0nh ki\u1ebfn th\u1ee9c m\u1edbi: H\u00ecnh thoi 1. Gi\u1edbi thi\u1ec7u h\u00ecnh thoi \u2013 GV v\u1ebd h\u00ecnh thoi ABCD tr\u00ean b\u1ea3ng l\u1edbp (n\u1ec1n l\u00e0 l\u01b0\u1edbi \u00f4 vu\u00f4ng) \u2192 GV ch\u1ec9 tay v\u00e0o h\u00ecnh v\u00e0 gi\u1edbi thi\u1ec7u: \u0110\u00e2y l\u00e0 h\u00ecnh thoi ABCD \u2192 HS nh\u00ecn h\u00ecnh tr\u00ean b\u1ea3ng l\u1edbp v\u00e0 n\u00f3i theo \u2192 Nh\u00f3m hai HS ch\u1ec9 tay v\u00e0o SGK v\u00e0 n\u00f3i: H\u00ecnh thoi ABCD. 2. Gi\u1edbi thi\u1ec7u t\u00ednh ch\u1ea5t v\u1ec1 c\u1ea1nh c\u1ee7a h\u00ecnh thoi \u2013 HS n\u00eau s\u1ed1 c\u1ea1nh c\u1ee7a m\u1ed9t h\u00ecnh thoi v\u00e0 k\u1ec3 t\u00ean c\u00e1c c\u1ea1nh c\u1ee7a h\u00ecnh thoi ABCD. \u2013 HS ho\u1ea1t \u0111\u1ed9ng theo nh\u00f3m b\u1ed1n: T\u00ecm hi\u1ec3u m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c c\u1ea1nh \u0111\u1ed1i di\u1ec7n c\u1ee7a h\u00ecnh thoi ABCD v\u00e0 quan h\u1ec7 v\u1ec1 \u0111\u1ed9 d\u00e0i c\u00e1c c\u1ea1nh c\u1ee7a h\u00ecnh thoi ABCD. C\u00e1c nh\u00f3m th\u1ea3o lu\u1eadn, tr\u00ecnh b\u00e0y v\u00e0 gi\u1ea3i th\u00edch nh\u1eadn x\u00e9t. (C\u00e1c c\u1ea1nh b\u1eb1ng nhau: d\u1ef1a v\u00e0o s\u1ed1 \u00f4 vu\u00f4ng ho\u1eb7c d\u00f9ng th\u01b0\u1edbc \u0111o; c\u00e1c c\u1ea1nh song song: nh\u1eadn bi\u1ebft qua tr\u1ef1c gi\u00e1c, kh\u00f4ng n\u00ean h\u1ecfi t\u1ea1i sao song song. N\u1ebfu c\u1ea7n, GV c\u00f3 th\u1ec3 gi\u1ea3i th\u00edch v\u1ec1 s\u1ef1 song song nh\u01b0 b\u00e0i h\u00ecnh b\u00ecnh h\u00e0nh.) \u2013 GV h\u1ec7 th\u1ed1ng nh\u1eadn x\u00e9t c\u1ee7a c\u00e1c nh\u00f3m. + C\u1ea1nh AB song song v\u1edbi c\u1ea1nh DC. + C\u1ea1nh AD song song v\u1edbi c\u1ea1nh BC. + B\u1ed1n c\u1ea1nh c\u1ee7a h\u00ecnh thoi b\u1eb1ng nhau. 228","\u2013 GV gi\u00fap HS kh\u00e1i qu\u00e1t ho\u00e1 t\u00ednh ch\u1ea5t c\u00e1c c\u1ea1nh c\u1ee7a h\u00ecnh thoi. GV h\u1ecfi \u0111\u1ec3 HS n\u00eau \u0111\u01b0\u1ee3c nh\u1eadn x\u00e9t: H\u00ecnh thoi ABCD c\u00f3 hai c\u1eb7p c\u1ea1nh \u0111\u1ed1i di\u1ec7n song song v\u00e0 \u0111\u1ed9 d\u00e0i b\u1ed1n c\u1ea1nh b\u1eb1ng nhau \u2192 H\u00ecnh thoi c\u00f3 hai c\u1eb7p c\u1ea1nh \u0111\u1ed1i di\u1ec7n song song v\u00e0 \u0111\u1ed9 d\u00e0i b\u1ed1n c\u1ea1nh b\u1eb1ng nhau. III. Th\u1ef1c h\u00e0nh, luy\u1ec7n t\u1eadp 1. Th\u1ef1c h\u00e0nh Ba\u0300i 1: \u2013 HS (nh\u00f3m b\u1ed1n) nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u, th\u1ea3o lu\u1eadn, nh\u1eadn bi\u1ebft h\u00ecnh n\u00e0o l\u00e0 h\u00ecnh thoi. \u2013 S\u1eeda b\u00e0i. + C\u00e1c nh\u00f3m tr\u00ecnh b\u00e0y: H\u00ecnh 3 l\u00e0 h\u00ecnh thoi (HS nh\u1eadn bi\u1ebft ch\u1ee7 y\u1ebfu qua tr\u1ef1c gi\u00e1c, GV kh\u00f4ng n\u00ean y\u00eau c\u1ea7u HS gi\u1ea3i th\u00edch). + Trong tr\u01b0\u1eddng h\u1ee3p HS l\u00e0m sai, v\u00ed d\u1ee5 c\u00e1c em n\u00f3i H\u00ecnh 4 c\u0169ng l\u00e0 h\u00ecnh thoi \u2192 GV h\u01b0\u1edbng d\u1eabn HS nh\u1eadn x\u00e9t xem b\u1ed1n c\u1ea1nh c\u1ee7a H\u00ecnh 4 c\u00f3 b\u1eb1ng nhau kh\u00f4ng. Ba\u0300i 2: \u2013 HS (nh\u00f3m \u0111\u00f4i) nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u, th\u1ea3o lu\u1eadn. \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb v\u1edbi b\u1ea1n. \u2013 S\u1eeda b\u00e0i, HS tr\u00ecnh b\u00e0y v\u00e0 gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m. a) C\u00e1c c\u1ea1nh c\u1ee7a h\u00ecnh thoi MNKL \u0111\u1ec1u d\u00e0i 5 cm (b\u1ed1n c\u1ea1nh c\u1ee7a h\u00ecnh thoi d\u00e0i b\u1eb1ng nhau m\u00e0 c\u1ea1nh MN d\u00e0i 5 cm). b) MO = OK, NO = OL (\u0111o). c) MK v\u00e0 NL vu\u00f4ng g\u00f3c v\u1edbi nhau (ki\u1ec3m tra b\u1eb1ng \u00ea-ke: g\u00f3c \u0111\u1ec9nh O; c\u1ea1nh ON, OK l\u00e0 g\u00f3c vu\u00f4ng). L\u01b0u \u00fd: B\u00e0i n\u00e0y, HS l\u00e0m quen v\u1edbi t\u00ednh ch\u1ea5t hai \u0111\u01b0\u1eddng ch\u00e9o qua m\u1ed9t h\u00ecnh c\u1ee5 th\u1ec3, kh\u00f4ng kh\u00e1i qu\u00e1t ho\u00e1 t\u00ednh ch\u1ea5t \u0111\u01b0\u1eddng ch\u00e9o c\u1ee7a h\u00ecnh thoi. Ba\u0300i 3: \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb nh\u00f3m b\u1ed1n. (GV l\u01b0u \u00fd \u1edf h\u00ecnh th\u1ee9 hai, c\u00e1c que t\u00ednh c\u1ee7a m\u1ed9t c\u1ea1nh ph\u1ea3i c\u00f9ng n\u1eb1m tr\u00ean m\u1ed9t \u0111\u01b0\u1eddng th\u1eb3ng, HS th\u01b0\u1eddng n\u00f3i: ph\u1ea3i ngay nhau.) \u2013 S\u1eeda b\u00e0i, c\u00e1c nh\u00f3m thi \u0111ua s\u1eeda ti\u1ebfp s\u1ee9c. 2. Luy\u1ec7n t\u1eadp B\u00e0i 1: \u2013 HS (nh\u00f3m \u0111\u00f4i) nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u v\u00e0 th\u1ea3o lu\u1eadn. + Th\u1ee9 t\u1ef1 \u0111\u1ecdc c\u00e1c \u0111\u1ec9nh c\u1ee7a h\u00ecnh thoi l\u00e0 A, B, C, D \u2192 V\u1ecb tr\u00ed c\u1ee7a \u0111i\u1ec3m C kho\u1ea3ng ch\u1ed7 n\u00e0o? \u2192 V\u1ecb tr\u00ed n\u00e0y ph\u1ea3i tho\u1ea3 m\u00e3n \u0111\u1ec3 ABCD l\u00e0 h\u00ecnh thoi. \u2013 HS l\u00e0m c\u00e1 nh\u00e2n (v\u1edf b\u00e0i t\u1eadp) r\u1ed3i chia s\u1ebb v\u1edbi b\u1ea1n. + V\u1ebd \u0111i\u1ec3m C. + V\u1ebd c\u00e1c \u0111o\u1ea1n th\u1eb3ng BC v\u00e0 DC. \u2013 Quan s\u00e1t h\u00ecnh v\u1eeba v\u1ebd xem c\u00f3 ph\u1ea3i l\u00e0 h\u00ecnh thoi ABCD kh\u00f4ng? 229","IV. V\u1eadn d\u1ee5ng, tr\u1ea3i nghi\u1ec7m B\u00e0i 2: \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb nh\u00f3m b\u1ed1n. \u2013 GV c\u00f3 th\u1ec3 g\u1ee3i \u00fd \u0111\u1ec3 HS l\u00e0m theo c\u00e1c b\u01b0\u1edbc. + V\u1ebd ch\u00ec tr\u00ean gi\u1ea5y k\u1ebb \u00f4 vu\u00f4ng. Ch\u1ea5m m\u1ed9t s\u1ed1 \u0111i\u1ec3m \u2192 D\u00f9ng th\u01b0\u1edbc th\u1eb3ng n\u1ed1i c\u00e1c \u0111i\u1ec3m (xem h\u00ecnh m\u1eabu). Ch\u1ea5m ti\u1ebfp m\u1ed9t s\u1ed1 \u0111i\u1ec3m r\u1ed3i th\u1ef1c hi\u1ec7n nh\u01b0 tr\u00ean cho t\u1edbi khi \u0111\u01b0\u1ee3c to\u00e0n b\u1ed9 h\u00ecnh th\u1ee9 nh\u1ea5t (SGK). + T\u00f4 m\u00e0u theo m\u1eabu ho\u1eb7c theo \u00fd th\u00edch. \u2013 Tr\u01b0ng b\u00e0y s\u1ea3n ph\u1ea9m tr\u00ean b\u1ea3ng l\u1edbp. \u2013 Mang s\u1ea3n ph\u1ea9m v\u1ec1 nh\u00e0, treo \u1edf g\u00f3c h\u1ecdc t\u1eadp. Ho\u1ea1t \u0111\u1ed9ng th\u1ef1c t\u1ebf C\u00e1c nh\u00f3m nh\u1eadn ra c\u00e1c v\u1eadt c\u00f3 d\u1ea1ng h\u00ecnh b\u00ecnh h\u00e0nh: \u2013 Trong SGK. \u2013 Trong th\u1ef1c t\u1ebf. B\u00e0i 56. X\u1ebeP H\u00ccNH, V\u1ebc H\u00ccNH (3 ti\u1ebft) A. Y\u00eau c\u1ea7u c\u1ea7n \u0111\u1ea1t \u2013 HS nh\u1eadn bi\u1ebft \u0111\u01b0\u1ee3c c\u00e1c h\u00ecnh ph\u1eb3ng v\u00e0 h\u00ecnh kh\u1ed1i \u0111\u00e3 h\u1ecdc; th\u1ef1c hi\u1ec7n \u0111\u01b0\u1ee3c vi\u1ec7c v\u1ebd h\u00ecnh thoi tr\u00ean gi\u1ea5y k\u1ebb \u00f4 vu\u00f4ng. \u2013 V\u1eadn d\u1ee5ng \u0111\u1ec3 gi\u1ea3i quy\u1ebft v\u1ea5n \u0111\u1ec1 li\u00ean quan \u0111\u1ebfn x\u1ebfp h\u00ecnh, g\u1ea5p, c\u1eaft h\u00ecnh. \u2013 HS c\u00f3 c\u01a1 h\u1ed9i ph\u00e1t tri\u1ec3n c\u00e1c n\u0103ng l\u1ef1c t\u01b0 duy v\u00e0 l\u1eadp lu\u1eadn to\u00e1n h\u1ecdc, giao ti\u1ebfp to\u00e1n h\u1ecdc, s\u1eed d\u1ee5ng c\u00f4ng c\u1ee5, ph\u01b0\u01a1ng ti\u1ec7n h\u1ecdc to\u00e1n, gi\u1ea3i quy\u1ebft v\u1ea5n \u0111\u1ec1 to\u00e1n h\u1ecdc v\u00e0 c\u00e1c ph\u1ea9m ch\u1ea5t ch\u0103m ch\u1ec9, tr\u00e1ch nhi\u1ec7m. B. \u0110\u1ed3 d\u00f9ng d\u1ea1y h\u1ecdc GV: H\u00ecnh v\u1ebd trong b\u00e0i (n\u1ebfu c\u1ea7n). HS: B\u1ed9 x\u1ebfp h\u00ecnh cho Luy\u1ec7n t\u1eadp 1, gi\u1ea5y k\u1ebb \u00f4 vu\u00f4ng cho Luy\u1ec7n t\u1eadp 5 v\u00e0 gi\u1ea5y d\u00f9ng cho b\u00e0i Vui h\u1ecdc. C. C\u00e1c ho\u1ea1t \u0111\u1ed9ng d\u1ea1y h\u1ecdc ch\u1ee7 y\u1ebfu I. Kh\u1edfi \u0111\u1ed9ng \u2013 K\u00ea\u0309 t\u00ean ca\u0301c hi\u0300nh kh\u00f4\u0301i \u0111a\u0303 ho\u0323c (kh\u00f4\u0301i l\u00e2\u0323p ph\u01b0\u01a1ng, kh\u00f4\u0301i h\u00f4\u0323p ch\u01b0\u0303 nh\u00e2\u0323t, kh\u00f4\u0301i tru\u0323, kh\u00f4\u0301i c\u00e2\u0300u). \u2013 Tro\u0300 ch\u01a1i \u0110i\u00ea\u0309m danh theo t\u00ean ca\u0301c hi\u0300nh kh\u00f4\u0301i. GV no\u0301i t\u00ean b\u00f4\u0301n hi\u0300nh kh\u00f4\u0301i \u0111a\u0303 ho\u0323c, ch\u0103\u0309ng ha\u0323n: \u201ckh\u00f4\u0301i tru\u0323, kh\u00f4\u0301i l\u00e2\u0323p ph\u01b0\u01a1ng, kh\u00f4\u0301i c\u00e2\u0300u, kh\u00f4\u0301i h\u00f4\u0323p ch\u01b0\u0303 nh\u00e2\u0323t\u201d. HS (ca\u0309 l\u01a1\u0301p) l\u00e2\u0300n l\u01b0\u01a1\u0323t \u0111i\u00ea\u0309m danh theo th\u01b0\u0301 t\u01b0\u0323 t\u00ean ca\u0301c kh\u00f4\u0301i h\u00f4\u0323p \u0111o\u0301: \u201ckh\u00f4\u0301i tru\u0323, kh\u00f4\u0301i l\u00e2\u0323p ph\u01b0\u01a1ng, kh\u00f4\u0301i c\u00e2\u0300u, kh\u00f4\u0301i h\u00f4\u0323p ch\u01b0\u0303 nh\u00e2\u0323t \u2013 kh\u00f4\u0301i tru\u0323, kh\u00f4\u0301i l\u00e2\u0323p ph\u01b0\u01a1ng, kh\u00f4\u0301i c\u00e2\u0300u, kh\u00f4\u0301i h\u00f4\u0323p ch\u01b0\u0303 nh\u00e2\u0323t \u2013 \u2026\u201d. 230","II. Th\u1ef1c h\u00e0nh, luy\u1ec7n t\u1eadp B\u00e0i 1: \u2013 T\u00ecm hi\u1ec3u b\u00e0i: \u2022 HS \u0111\u1ecdc y\u00eau c\u1ea7u.\t\t \u2022 Quan s\u00e1t h\u00ecnh v\u1ebd, em nh\u1eadn bi\u1ebft \u0111i\u1ec1u g\u00ec? (D\u00f9ng b\u1ed9 x\u1ebfp h\u00ecnh \u0111\u1ec3 x\u1ebfp m\u1ed9t h\u00ecnh b\u00ecnh h\u00e0nh.) \u2013 HS (nh\u00f3m \u0111\u00f4i) th\u1ea3o lu\u1eadn t\u00ecm c\u00e1ch l\u00e0m (m\u1ed7i HS x\u1ebfp m\u1ed9t h\u00ecnh r\u1ed3i chia s\u1ebb v\u1edbi b\u1ea1n). B\u00e0i\u2013 S\u1eeda b\u00e0i, GV khuy\u1ebfn kh\u00edch HS m\u00f4 t\u1ea3 c\u00e1ch x\u1ebfp (k\u1ebft h\u1ee3p v\u1edbi \u0110DHT). B5\u00e06i X\u1ebeP H\u00ccNH, V\u1ebc H\u00ccNHV\u00ed d\u1ee5: H\u00ecnh b\u00ecnh h\u00e0nh \u0111\u01b0\u1ee3c x\u1ebfp b\u1edfi 1 h\u00ecnh vu\u00f4ng, 5 h\u00ecnh tam gi\u00e1c v\u00e0 1 h\u00ecnh b\u00ecnh h\u00e0nh 56 X\u1ebeP H\u00ccNH, V\u1ebc H\u00ccNH... b\u00ecnLh\u01b0hu\u00e0n\u00fd:hVk\u1edbhi\u00e1cc\u00e11tcu1n\u1ef3hth\u00f3X\u00edmc\u1ebfXhHp.\u1ebfSphh\u00echno\u00ec\u00e0hnn.ht.h\u00e0nh s\u1edbm, c\u00e1c em c\u00f3 th\u1ec3 t\u01b0\u1edfng t\u01b0\u1ee3ng v\u00e0 x\u1ebfp m\u1ed9t h\u00ecnh B\u00e0i 2: \u2013 HS hoa\u0323t \u0111\u00f4\u0323ng nho\u0301m b\u1ed1n. + Nh\u00e2\u0323n bi\u00ea\u0301t y\u00eau c\u00e2\u0300u. + Tha\u0309o lu\u00e2\u0323n ca\u0301ch th\u01b0\u0301c GQV\u0110. B\u00e0iXa\u0301c \u0111i\u0323nh quy lu\u1eadt c\u1ee7a d\u00e3y h\u00ecnh \u0111\u01b0\u1ee3c l\u1eb7p l\u1ea1i theo h\u00ecnh d\u1ea1ng. 56 X\u1ebeP H\u00ccNH, V\u1ebc H\u00ccNHTh\u1ee9 t\u1ef1 d\u00e3y h\u00ecnh: H\u00ecnh b\u00ecnh h\u00e0nh H\u00ecnHh\u00eccnhh\u1eef nthha\u1eadty\u2013vH\u00e0\u00ecnoh.b?\u00ec.nlh\u00e0hh\u00e0\u00ecnnhh\u2013gH\u00ec\u00ec?nhHt\u00echnohi. b\u00ecnh h\u00e0nh a) H\u00ecnh vu\u00f4n2g2\u2013 H\u00ecnh thay v\u00e0o .?. l\u00e0 h\u00ecnh g\u00ec? 1 X\u1ebfp h\u00ecnh. .? .?. B\u00e0iH\u00ecnh ti\u1ebfp theo h\u00ecnh ch\u1eef nh\u1eadt l\u00e0 h\u00ecnh b\u00ecnh h\u00e0nh. 56 X\u1ebeP H\u00ccNH, V\u1ebc H\u00ccNHTh\u1eed th\u00e1ch . H\u00ecnh th\u1ee9 14 l\u00e0 h\u00ecnh g\u00ec? H\u00ecnh \u0111\u00f3 c\u00f3 m\u00e0u g\u00ec? th\u1eed th\u00e1ch H\u00ecnh th\u1ee9 14 l\u00e0 h\u00ecnh g\u00ec? H\u00ecnh \u0111\u00f3 c\u00f3 m\u00e0u g\u00ec? \u2013 H\u00ecnh d\u1ea1ng: H\u00ecnthh\u1eedtatmh\u00e1gcih\u00e1c \u2013 H\u00ecnh thoi \u2013 H\u00ecnh tr\u00f2n. 1 X\u1ebfp h\u00ecnh. H\u00ecnh b\u00ecnh h\u00e0nh 2 H\u00ecnh thay v\u00e0o .?. l\u00e0 h\u00ecnh g\u00ec? H\u00ecnh th\u1ee9 143tr3ongMdM\u00e3\u1ed7yi\u1ed7hhi\u00ecn\u00echnh\u00echnl\u00e0hdh\u01b0d\u00ecn\u1edb\u01b0h\u1edbit\u0111hi o\u00e2\u0111iy\u00e2(vyc\u00ec \u00f33c\u00f3\u00d7ba4boa+o2nh=nih1\u00ea4iu\u00ea; udk\u00e3hky\u1ed1hhi\u1ed1\u00ecnli\u1eadhlp\u1ead\u0111p\u01b0p\u1ee3hpc\u01b0hl\u1eb7\u01a1\u01b0p\u01a1nl\u1ea1gni ?g4 ?l\u1ea7n .?. v\u00e0 th\u00eam 2 h\u00ecnh n\u1eefa l\u00e0 h\u00ecnh th\u1ee9 14: h\u00ecnh thoi). \u2013 M\u00e0u s\u1eafc: \u0110\u1ecf \u2013 Cam \u2013 T\u00edm \u2013 Xanh l\u00e1 \u2013 Xanh da tr\u1eddi. H\u00ecnh th\u1ee9 14 trong d\u00e3y h\u00ecnhHl\u00e0\u00ecnmh\u00e0uthx\u1ee9an1h4l\u00e1l\u00e0(v\u00ech5\u00ecn\u00d7h2g+\u00ec?4 =HH1\u00ecn4\u00ecnh; dh\u0111\u00e3yb\u00f3h\u00ecnc\u00ecn\u00f3hh mh\u0111\u01b0\u00e0\u00e0\u1ee3nuchlg\u1eb7p\u00ec?l\u1ea1i 2 l\u1ea7n v\u00e0 th\u00eam 4 h\u00ecnhthn\u1eed2\u1eeftha\u00e1lc\u00e0hHh\u00ec\u00ecnnhhtht\u1ee9ha14y: mv\u00e0\u00e0uox.a?n.hl\u00e0l\u00e1)h. \u00ecnh g\u00ec? .?. ... \u2013 K\u1ebft l3u\u1eadn: H\u00ecnh th\u1ee9 14 l\u00e0 h\u00ecnh thoi m\u00e0u xanh l\u00e1. M\u1ed7i h\u00ecnh d\u01b0\u1edbi \u0111\u00e2HyH\u00ecc\u00ecnn\u00f3hhbAtha\u1ee9o n14hil\u00ea\u00e0uhk\u00ecnhh\u1ed1gi l\u00ec\u1ead? pH\u00ecpnhh\u01b0\u0111\u01a1H\u00f3n\u00ecncgh\u00f3? Bm\u00e0u g\u00ec? 44a) th\u1eed th\u00e1ch H\u00ecnh A H\u00ecnh B 231 Quan s\u00e1t h\u00ecnh b\u00ean. nhi\u00eau kh\u1ed1i, trong \u0111\u00f3 c\u00f3 QHu\u00ecannhsb\u00e1\u00eatnhc\u00ecn\u00f3ht\u1ea5bt\u00eacn\u1ea3. bao","B\u00e0i 3: \u2013 C\u00f3 th\u1ec3 t\u1ed5 ch\u1ee9c \u0111\u1ec3 c\u00e1c nh\u00f3m GQV\u0110. B\u01b0\u1edbc 1: T\u00ecm hi\u1ec3u v\u1ea5n \u0111\u1ec1 Nh\u1eadn bi\u1ebft v\u1ea5n \u0111\u1ec1 c\u1ea7n gi\u1ea3i quy\u1ebft: X\u00e1c \u0111\u1ecbnh s\u1ed1 kh\u1ed1i l\u1eadp ph\u01b0\u01a1ng \u1edf h\u00ecnh A v\u00e0 h\u00ecnh B. B\u01b0\u1edbc 2: L\u1eadp k\u1ebf ho\u1ea1ch N\u00eau \u0111\u01b0\u1ee3c c\u00e1ch th\u1ee9c GQV\u0110: D\u1ef1a v\u00e0o c\u00e1c h\u00ecnh \u0111\u00e3 cho \u2192 Quy lu\u1eadt x\u1ebfp h\u00ecnh theo t\u1eebng h\u00e0ng \t \u2192 X\u00e1c \u0111\u1ecbnh s\u1ed1 kh\u1ed1i l\u1eadp ph\u01b0\u01a1ng x\u1ebfp \u1edf c\u00e1c h\u00e0ng ti\u1ebfp theo \t \u2192 X\u00e1c \u0111\u1ecbnh s\u1ed1 kh\u1ed1i l\u1eadp ph\u01b0\u01a1ng x\u1ebfp \u1edf t\u1eebng h\u00ecnh. B\u01b0\u1edbc 3: Ti\u1ebfn h\u00e0nh k\u1ebf ho\u1ea1ch C\u00e1c nh\u00f3m th\u1ef1c hi\u1ec7n v\u00e0 tr\u00ecnh b\u00e0y. Quan s\u00e1t h\u00ecnh \u1ea3nh c\u00e1c h\u00ecnh. \u2192 S\u1ed1 kh\u1ed1i x\u1ebfp \u1edf h\u00e0ng th\u1ee9 nh\u1ea5t (tr\u00ean c\u00f9ng) + 2 = S\u1ed1 kh\u1ed1i x\u1ebfp \u1edf h\u00e0ng th\u1ee9 hai. S\u1ed1 kh\u1ed1i x\u1ebfp \u1edf h\u00e0ng th\u1ee9 hai + 3 = S\u1ed1 kh\u1ed1i x\u1ebfp \u1edf h\u00e0ng th\u1ee9 ba. S\u1ed1 kh\u1ed1i x\u1ebfp \u1edf h\u00e0ng th\u1ee9 ba + 4 = S\u1ed1 kh\u1ed1i x\u1ebfp \u1edf h\u00e0ng th\u1ee9 t\u01b0. \u2192 Quy lu\u1eadt c\u1ee7a c\u00e1c kh\u1ed1i l\u1eadp ph\u01b0\u01a1ng \u0111\u01b0\u1ee3c x\u1ebfp trong h\u00ecnh l\u00e0: S\u1ed1 kh\u1ed1i x\u1ebfp \u1edf h\u00e0ng d\u01b0\u1edbi = S\u1ed1 kh\u1ed1i x\u1ebfp \u1edf h\u00e0ng tr\u00ean li\u1ec1n k\u1ec1 + S\u1ed1 th\u1ee9 t\u1ef1 c\u1ee7a h\u00e0ng sau \u2192 D\u00e3y s\u1ed1\t 1;\t 3; 6; 10 \u2192 D\u1ef1a v\u00e0o quy lu\u1eadt x\u1ebfp h\u00ecnh theo t\u1eebng h\u00e0ng \u2192 Quy lu\u1eadt c\u1ee7a d\u00e3y s\u1ed1: S\u1ed1 sau = S\u1ed1 ngay tr\u01b0\u1edbc + S\u1ed1 th\u1ee9 t\u1ef1 c\u1ee7a s\u1ed1 sau +2 +3 +4 \u2192 1 3 6 10 \u21921+3=4 H\u00ecnh A c\u00f3 4 kh\u1ed1i l\u1eadp ph\u01b0\u01a1ng. 1 + 3 + 6 + 10 = 20 H\u00ecnh B c\u00f3 20 kh\u1ed1i l\u1eadp ph\u01b0\u01a1ng. C\u0169ng c\u00f3 th\u1ec3 gi\u1ea3i th\u00edch vi\u1ec7c t\u00ecm quy lu\u1eadt x\u1ebfp h\u00ecnh theo c\u00e1c c\u00e1ch kh\u00e1c. GV gi\u00fap c\u00e1c em di\u1ec5n \u0111\u1ea1t. B\u01b0\u1edbc 4: Ki\u1ec3m tra l\u1ea1i X\u00e1c \u0111\u1ecbnh l\u1ea1i xem d\u00e3y s\u1ed1 c\u00f3 \u0111\u00fang v\u1edbi s\u1ed1 kh\u1ed1i c\u1ee7a t\u1eebng h\u00ecnh kh\u00f4ng? \u2013 GV h\u1ec7 th\u1ed1ng l\u1ea1i vi\u1ec7c l\u00e0m c\u1ee7a c\u00e1c nh\u00f3m. X\u1ebfp h\u00ecnh \u2192 Quy lu\u1eadt \u2192 D\u00e3y s\u1ed1 \u2192 T\u00ecm s\u1ed1 kh\u1ed1i l\u1eadp ph\u01b0\u01a1ng c\u00f3 \u1edf trong t\u1eebng h\u00ecnh. 232","c B\u00e0i 4: \u2013 HS (nh\u00f3m \u0111\u00f4i) \u0111\u1ecdc c\u00e1c y\u00eau c\u1ea7u, th\u1ea3o lu\u1eadn, nh\u1eadn bi\u1ebft c\u00e1c y\u00eau c\u1ea7u c\u1ee7a b\u00e0i. \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb v\u1edbi b\u1ea1n. \u2013 S\u1eeda b\u00e0i: a) GV khuy\u1ebfn kh\u00edch nhi\u1ec1u nh\u00f3m n\u00eau k\u1ebft qu\u1ea3 (v\u1eeba ch\u1ec9 v\u00e0o h\u00ecnh v\u1ebd, v\u1eeba \u0111\u1ebfm). b) GV khuy\u1ebfn kh\u00edch HS gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m. V\u00ed d\u1ee5: \u2022 1 h\u00ecnh: 12 kh\u1ed1i g\u1ed3m 7 kh\u1ed1i tr\u1ee5, 5 kh\u1ed1i h\u1ed9p ch\u1eef nh\u1eadt. \u2022 5 h\u00ecnh (g\u1ea5p 5 l\u1ea7n): 60 kh\u1ed1i g\u1ed3m 35 kh\u1ed1i tr\u1ee5, 25 kh\u1ed1i h\u1ed9p ch\u1eef nh\u1eadt. (HS c\u00f3 th\u1ec3 c\u00f3 nhi\u1ec1u c\u00e1ch gi\u1ea3i th\u00edch kh\u00e1c, c\u00e1c c\u00e1ch gi\u1ea3i th\u00edch h\u1ee3p l\u00ed \u0111\u1ec1u \u0111\u01b0\u1ee3c ch\u1ea5p nh\u1eadn.) III. V\u1eadn d\u1ee5ng, tr\u1ea3i nghi\u1ec7m B\u00e0i 5: \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb nh\u00f3m b\u1ed1n. \u2013 GV c\u00f3 th\u1ec3 g\u1ee3i \u00fd \u0111\u1ec3 HS l\u00e0m theo c\u00e1c b\u01b0\u1edbc. + V\u1ebd ch\u00ec tr\u00ean gi\u1ea5y k\u1ebb \u00f4 vu\u00f4ng. Ch\u1ea5m m\u1ed9t s\u1ed1 \u0111i\u1ec3m \u2192 D\u00f9ng th\u01b0\u1edbc th\u1eb3ng n\u1ed1i c\u00e1c \u0111i\u1ec3m (xem h\u00ecnh m\u1eabu). Ch\u1ea5m ti\u1ebfp m\u1ed9t s\u1ed1 \u0111i\u1ec3m r\u1ed3i th\u1ef1c hi\u1ec7n nh\u01b0 tr\u00ean cho t\u1edbi khi \u0111\u01b0\u1ee3c to\u00e0n b\u1ed9 h\u00ecnh nh\u01b0 SGK. + T\u00f4 m\u00e0u theo m\u1eabu ho\u1eb7c theo \u00fd th\u00edch. \u2013 Tr\u01b0ng b\u00e0y s\u1ea3n ph\u1ea9m tr\u00ean b\u1ea3ng l\u1edbp. \u2013 Mang s\u1ea3n ph\u1ea9m v\u1ec1 nh\u00e0, treo \u1edf g\u00f3c h\u1ecdc t\u1eadp. Vui h\u1ecdc vui \u2013h \u1ecd GV c\u00f3 th\u1ec3 h\u01b0\u1edbng d\u1eabn cho HS th\u1ef1c hi\u1ec7n theo nh\u00f3m \u0111\u00f4i (ho\u1eb7c nh\u00f3m b\u1ed1n): M\u1ed7i HS g\u1ea5ap)\u2013 cG\u1eaft\u1ea52ph\u00ecvn\u00e0hcth\u1eafotic(t\u00e1hceot\u1eddc\u00e1gcib\u1ea5\u01b0y\u1edbmc t\u00e0roung(thSGeoK)h. \u00ecnh v\u1ebd) \u0111\u1ec3 t\u1ea1o th\u00e0nh c\u00e1c h\u00ecnh thoi. thb\u00e0\u2013n) hKmDhi\u00f9\u1ed9\u0111tn\u00e3bg\u1ee9ccc\u1eaft\u00e1trxcaonnhhg\u00ec.n, hkhtuhyo\u1ebfni vk\u1eebh\u00edachc\u1eafc\u00e1tc\u0111e\u1ec3mtt\u1ea1roontghn\u00e0hn\u00f3hmmc\u00f9\u1ed9ntgbt\u1ee9\u01b0\u1edfcntgrat\u01b0n\u1ee3hn. g v\u00e0 trang tr\u00ed L\u01b0u \u00fd: HS c\u00f3 th\u1ec3 g\u1ea5p \u2013 c\u1eaft s\u1ed1 l\u01b0\u1ee3ng h\u00ecnh thoi tu\u1ef3 \u00fd \u0111\u1ec3 c\u00f3 th\u1ec3 trang tr\u00ed h\u00ecnh th\u00e0nh b\u1ee9c tranh theo SGK ho\u1eb7c theo t\u01b0\u1edfng t\u01b0\u1ee3ng ri\u00eang c\u1ee7a nh\u00f3m m\u00ecnh. 233","B\u00e0i 57. MI-LI-M\u00c9T VU\u00d4NG (2 ti\u1ebft) A. Y\u00eau c\u1ea7u c\u1ea7n \u0111\u1ea1t \u2013 HS nh\u1eadn bi\u1ebft \u0111\u1ed9 l\u1edbn 1 mm2 (di\u1ec7n t\u00edch h\u00ecnh vu\u00f4ng c\u00f3 c\u1ea1nh d\u00e0i 1 mm); nh\u1eadn bi\u1ebft t\u00ean g\u1ecdi, k\u00ed hi\u1ec7u, quan h\u1ec7 gi\u1eefa mi-li-m\u00e9t vu\u00f4ng v\u00e0 x\u0103ng-ti-m\u00e9t vu\u00f4ng; \u0111\u1ecdc, vi\u1ebft c\u00e1c s\u1ed1 \u0111o theo \u0111\u01a1n v\u1ecb mi-li-m\u00e9t vu\u00f4ng; th\u1ef1c hi\u1ec7n \u0111\u01b0\u1ee3c vi\u1ec7c \u01b0\u1edbc l\u01b0\u1ee3ng c\u00e1c k\u1ebft qu\u1ea3 \u0111o l\u01b0\u1eddng trong tr\u01b0\u1eddng h\u1ee3p \u0111\u01a1n gi\u1ea3n, th\u1ef1c hi\u1ec7n \u0111\u01b0\u1ee3c vi\u1ec7c chuy\u1ec3n \u0111\u1ed5i v\u00e0 t\u00ednh to\u00e1n v\u1edbi c\u00e1c s\u1ed1 \u0111o di\u1ec7n t\u00edch mi-li-m\u00e9t vu\u00f4ng, x\u0103ng-ti-m\u00e9t vu\u00f4ng. \u2013 V\u1eadn d\u1ee5ng gi\u1ea3i quy\u1ebft c\u00e1c v\u1ea5n \u0111\u1ec1 \u0111\u01a1n gi\u1ea3n li\u00ean quan \u0111\u1ebfn \u0111\u01a1n v\u1ecb \u0111o di\u1ec7n t\u00edch, bi\u1ec3u \u0111\u1ed3 c\u1ed9t. \u2013 HS c\u00f3 c\u01a1 h\u1ed9i \u0111\u1ec3 ph\u00e1t tri\u1ec3n c\u00e1c n\u0103ng l\u1ef1c t\u01b0 duy v\u00e0 l\u1eadp lu\u1eadn to\u00e1n h\u1ecdc, giao ti\u1ebfp to\u00e1n h\u1ecdc, m\u00f4 hi\u0300nh ho\u00e1 toa\u0301n ho\u0323c, gi\u1ea3i quy\u1ebft v\u1ea5n \u0111\u1ec1 to\u00e1n h\u1ecdc v\u00e0 c\u00e1c ph\u1ea9m ch\u1ea5t tr\u00e1ch nhi\u1ec7m, y\u00eau n\u01b0\u1edbc. B. \u0110\u1ed3 d\u00f9ng d\u1ea1y h\u1ecdc GV: Gi\u1ea5y k\u1ebb \u00f4 vu\u00f4ng, m\u1ed7i c\u1ea1nh 10 \u00f4 vu\u00f4ng d\u00f9ng cho n\u1ed9i dung b\u00e0i h\u1ecdc, h\u00ecnh \u1ea3nh b\u00e0i Th\u1ef1c h\u00e0nh 3, b\u00e0i Luy\u1ec7n t\u1eadp 1 v\u00e0 b\u00e0i Kh\u00e1m ph\u00e1 (n\u1ebfu c\u1ea7n). HS: Gi\u1ea5y k\u1ebb \u00f4 vu\u00f4ng, c\u1ea1nh m\u1ed7i \u00f4 vu\u00f4ng d\u00e0i 1 mm d\u00f9ng cho m\u1ee5c Gi\u1edbi thi\u1ec7u mi-li-m\u00e9t vu\u00f4ng (GV chu\u1ea9n b\u1ecb). C. C\u00e1c ho\u1ea1t \u0111\u1ed9ng d\u1ea1y h\u1ecdc ch\u1ee7 y\u1ebfu I. Kh\u1edfi \u0111\u1ed9ng B\u00e0i GV c\u00f3 th\u1ec3 cho HS ch\u01a1i: \u201c\u0110\u1ed1 b\u1ea1n?\u201d 57 MI-LI-M\u00c9T VU\u00d4NG GV: \u0110\u1ed1 b\u1ea1n, \u0111\u1ed1 b\u1ea1n.\t\t\t HS: \u0110\u1ed1 g\u00ec? \u0110\u1ed1 g\u00ec? GV: K\u1ec3 t\u00ean c\u00e1c \u0111\u01a1n v\u1ecb \u0111o di\u1ec7n t\u00edch \u0111\u00e3 h\u1ecdc.\t Di\u1ec7n t\u00edch m\u1ea3nh gi\u1ea5y HS: x\u0103ng-ti-m\u00e9t vu\u00f4ng, \u0111\u1ec1-xi-m\u00e9t vu\u00f4ng, m\u00e9t vu\u00f4ng. \t\t h\u00ecnh vu\u00f4ng c\u1ee1 m\u00f3ng GV: \u0110\u1ed1 b\u1ea1n, \u0111\u1ed1 b\u1ea1n.\t\t\t\t ng\u00f3n tay tr\u1ecf kho\u1ea3ng HS: \u0110\u1ed1 g\u00ec? \u0110\u1ed1 g\u00ec? 1 cm2. GV: 1 cm2 l\u00e0 di\u1ec7n t\u00edch c\u1ee7a h\u00ecnh vu\u00f4ng c\u00f3 c\u1ea1nh d\u00e0i bao nhi\u00eau? HS: 1 cm. GV: Tr\u00ean b\u00e0n tay b\u1ea1n, c\u00e1i g\u00ec c\u00f3 di\u1ec7n t\u00edch kho\u1ea3ng 1 cm2? HS: M\u00f3ng ng\u00f3n tr\u1ecf. \u2022\t Mi-li-m\u00e9t\tvu\u00f4ng\tl\u00e0\tm\u1ed9t\t\u0111 \u2022\t Mi-li-m\u00e9t\tvu\u00f4ng\tvi\u1ebft\tt\u1eaft\tl\u00e0 GV: Di\u1ec7n t\u00edch m\u00f3ng ng\u00f3n \u00fat? \t\t\t \u2022\t 1\tmm2 l\u00e0 di\u1ec7n t\u00edch c\u1ee7a h\u00ecn HS: B\u00e9 h\u01a1n 1 cm2. GV: Khi \u0111\u00f3 ta ph\u1ea3i d\u00f9ng \u0111\u01a1n v\u1ecb di\u1ec7n t\u00edch b\u00e9 h\u01a1n. \u2192 Gi\u1edbi thi\u1ec7u b\u00e0i. II. Kh\u00e1m ph\u00e1, h\u00ecnh th\u00e0nh ki\u1ebfn th\u1ee9c m\u1edbi: Mi-li-m\u00e9t vu\u00f4ng 1 mm20 cm 1 1. Gi\u1edbi thi\u1ec7u mi-li-m\u00e9t vu\u00f4ng 0 cm 1 \u2013 HS (nh\u00f3m \u0111\u00f4i) quan s\u00e1t h\u00ecnh \u1ea3nh b\u00ean tr\u00e1i (SGK). H\u00ecnh vu\u00f4ng b\u00e9 x\u00edu, m\u00e0u v\u00e0ng c\u00f3 c\u1ea1nh d\u00e0i bao nhi\u00eau? (1 mm) Di\u1ec7n t\u00edch h\u00ecnh vu\u00f4ng n\u00e0y l\u00e0 m\u1ed9t mi-li-m\u00e9t vu\u00f4ng. 234","\u2022 Mi-li-m\u00e9t vu\u00f4ng l\u00e0 \u0111\u01a1n v\u1ecb \u0111o \u0111\u1ea1i l\u01b0\u1ee3ng n\u00e0o? (Mi-li-m\u00e9t vu\u00f4ng l\u00e0 \u0111\u01a1n v\u1ecb \u0111o di\u1ec7n t\u00edch \u2192 GV vi\u1ebft b\u1ea3ng.) \u2022 GV gi\u1edbi thi\u1ec7u c\u00e1ch v\u1ebft t\u1eaft mi-li-m\u00e9t vu\u00f4ng. GV vi\u1ebft: cm \u2192 HS \u0111\u1ecdc: x\u0103ng-ti-m\u00e9t. GV vi\u1ebft: cm2 \u2192 HS \u0111\u1ecdc: x\u0103ng-ti-m\u00e9t vu\u00f4ng. GV vi\u1ebft: mm \u2192 HS \u0111\u1ecdc: mi-li-m\u00e9t. GV vi\u1ebft: mm2 \u2192 HS \u0111\u1ecdc: mi-li-m\u00e9t vu\u00f4ng. \u2192 GV vi\u1ebft b\u1ea3ng: Mi-li-m\u00e9t vu\u00f4ng vi\u1ebft t\u1eaft l\u00e0 mm2. \u2022 1 mm2 l\u00e0 di\u1ec7n t\u00edch c\u1ee7a h\u00ecnh vu\u00f4ng c\u00f3 c\u1ea1nh d\u00e0i bao nhi\u00eau? (1 mm) \u2192 GV vi\u1ebft b\u1ea3ng: 1 mm2 l\u00e0 di\u1ec7n t\u00edch h\u00ecnh vu\u00f4ng c\u00f3 c\u1ea1ch d\u00e0i 1 mm. \u2013 Nh\u1eadn bi\u1ebft \u0111\u1ed9 l\u1edbn c\u1ee7a mm2, th\u1ef1c h\u00e0nh \u0111\u1ecdc, vi\u1ebft mi-li-m\u00e9t vu\u00f4ng. \u2022 Vi\u1ebft theo m\u1eabu r\u1ed3i \u0111\u1ecdc. 0 cm 1 0 cm 1 0 cm 1 0 cm 1 0 cm 1 0 cm 1 2 mm2 \u2026\u2026\u2026. \u2026\u2026\u2026. GV l\u01b0u \u00fd HS: s\u1ed1 v\u00e0 k\u00ed hi\u1ec7u c\u00e1ch nhau m\u1ed9t ch\u00fat (kho\u1ea3ng n\u1eeda th\u00e2n con ch\u1eef o). \u2022 Nh\u1eefng v\u1eadt n\u00e0o c\u00f3 di\u1ec7n t\u00edch kho\u1ea3ng 1 mm2? (D\u1ea5u ch\u1ea5m \u0111\u1eadm \u1edf \u0111\u1ea7u d\u00f2ng tr\u00ean, l\u1ed7 g\u00e0i tr\u00ean d\u00e2y \u0111\u1ed3ng h\u1ed3, h\u1ea1t m\u00e8, n\u1ed1t ru\u1ed3i, ...). 2. Quan h\u1ec7 gi\u1eefa mi-li-m\u00e9t vu\u00f4ng v\u00e0 x\u0103ng-ti-m\u00e9t vu\u00f4ng \u2013 HS (nh\u00f3m b\u1ed1n) th\u1ea3o lu\u1eadn, nh\u1eadn bi\u1ebft quan h\u1ec7 gi\u1eefa mi-li-m\u00e9t vu\u00f4ng v\u1edbi x\u0103ng-ti-m\u00e9t vu\u00f4ng. \u2013 HS quan s\u00e1t h\u00ecnh \u1ea3nh \u1edf SGK (GV gi\u1ea3i th\u00edch h\u00ecnh b\u00ean tr\u00e1i ph\u00f3ng l\u1edbn \u0111\u01b0\u1ee3c h\u00ecnh b\u00ean ph\u1ea3i), HS nh\u1eadn bi\u1ebft: \u2022 H\u00ecnh vu\u00f4ng m\u00e0u xanh c\u00f3 1 mm2 1 mm2 c\u1ea1nh 1 cm n\u00ean di\u1ec7n t\u00edch l\u00e0 1 cm2. 1 mm \u2022 H\u00ecnh vu\u00f4ng m\u00e0u v\u00e0ng c\u00f3 di\u1ec7n t\u00edch 1 mm2. 0 cm 1 1 mm \u2013 HS th\u1ea3o lu\u1eadn t\u00ecm c\u00e1ch l\u00e0m. 0 cm 1 \u2022 M\u1ed7i \u00f4 vu\u00f4ng nh\u1ecf c\u1ee7a h\u00ecnh 1 cm vu\u00f4ng m\u00e0u xanh c\u00f3 di\u1ec7n t\u00edch 1 mm2. \u2022 T\u00ecm xem h\u00ecnh vu\u00f4ng m\u00e0u xanh g\u1ed3m bao nhi\u00eau \u00f4 vu\u00f4ng nh\u1ecf. \u2192 \u0110\u1ebfm ho\u1eb7c t\u00ednh (theo h\u00e0ng, theo c\u1ed9t). 1 cm \u2013 M\u1ed9t v\u00e0i nh\u00f3m tr\u00ecnh b\u00e0y. \u2013 C\u1ea3 l\u1edbp \u0111\u1ebfm theo tay ch\u1ec9 c\u1ee7a GV. \u2022 H\u00e0ng \u0111\u1ea7u \u0111\u1ebfm theo \u00f4 1 mm2: 1, 2, 3, \u2026, 10 mm2. \u2022 \u0110\u1ebfm c\u00e1c h\u00e0ng theo 10 mm2: 10, 20, 30, \u2026, 100 mm2. \u2192 1 cm2 = 100 mm2 100 mm2 = 1 cm2 (GV vi\u1ebft b\u1ea3ng, HS l\u1eb7p l\u1ea1i nhi\u1ec1u l\u1ea7n.) 235","III. Th\u1ef1c h\u00e0nh, luy\u1ec7n t\u1eadp Th\u1ef1c h\u00e0nh Ba\u0300i 1: \u2013 HS (nh\u00f3m \u0111\u00f4i) t\u00ecm hi\u1ec3u b\u00e0i, nh\u1eadn bi\u1ebft: \u2022 Y\u00eau c\u1ea7u c\u1ee7a b\u00e0i: S\u1ed1? \u2022 T\u00ecm th\u1ebf n\u00e0o? (chuy\u1ec3n \u0111\u1ed5i \u0111\u01a1n v\u1ecb \u0111o) \u2013 H\u1ecfi nhanh \u0111\u00e1p g\u1ecdn \u00f4n l\u1ea1i c\u00e1ch chuy\u1ec3n \u0111\u1ed5i \u0111\u01a1n v\u1ecb (coi tr\u0103m l\u00e0 \u0111\u01a1n v\u1ecb \u0111\u1ebfm ho\u1eb7c th\u1ef1c hi\u1ec7n nh\u00e2n nh\u1ea9m v\u1edbi 100, chia nh\u1ea9m cho 100). \u2022 M\u1ed9t x\u0103ng-ti-m\u00e9t vu\u00f4ng b\u1eb1ng bao nhi\u00eau mi-li-m\u00e9t vu\u00f4ng? (m\u1ed9t tr\u0103m mi-li-m\u00e9t vu\u00f4ng) N\u0103m x\u0103ng-ti-m\u00e9t vu\u00f4ng? (n\u0103m tr\u0103m mi-li-m\u00e9t vu\u00f4ng) M\u01b0\u1eddi b\u1ea3y x\u0103ng-ti-m\u00e9t vu\u00f4ng\u00a0? (m\u01b0\u1eddi b\u1ea3y tr\u0103m mi-li-m\u00e9t vu\u00f4ng) \u2192 vi\u1ebft? (1 700 mm2) \u2022 T\u00e1m tr\u0103m mi-li-m\u00e9t vu\u00f4ng b\u1eb1ng bao nhi\u00eau x\u0103ng-ti-m\u00e9t vu\u00f4ng? (t\u00e1m x\u0103ng-ti-m\u00e9t vu\u00f4ng) M\u1ed9t ngh\u00ecn n\u0103m tr\u0103m mi-li-m\u00e9t vu\u00f4ng? (m\u01b0\u1eddi l\u0103m tr\u0103m mi-li-m\u00e9t vu\u00f4ng\u00a0t\u1ee9c l\u00e0 m\u01b0\u1eddi l\u0103m x\u0103ng-ti-m\u00e9t vu\u00f4ng) \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n. \u2013 S\u1eeda b\u00e0i, GV c\u0169ng c\u00f3 th\u1ec3 cho HS ch\u01a1i ti\u1ebfp s\u1ee9c (ho\u1eb7c truy\u1ec1n \u0111i\u1ec7n) \u0111\u1ec3 s\u1eeda b\u00e0i (t\u1ea1o \u0111i\u1ec1u ki\u1ec7n cho nhi\u1ec1u HS \u0111i\u1ec1n \/ n\u00f3i). GV s\u1eeda c\u1eb7n k\u1ebd c\u00e2u c). V\u00ed d\u1ee5\u00a0: 3 cm2 5 mm2 = \u2026 mm2 3 cm2 = 300 mm2 \t 300 mm2 + 5 mm2 = 305 mm2 \t 3 cm2 5 mm2 = 305 mm2 \u2026 Ba\u0300i 2: \u2013 HS \u0111\u1ecdc \u0111\u1ec1 b\u00e0i, nh\u1eadn bi\u1ebft \u0111\u01b0\u1ee3c v\u1ea5n \u0111\u1ec1 c\u1ea7n gi\u1ea3i quy\u1ebft: Th\u1ef1c hi\u1ec7n c\u00e1c ph\u00e9p t\u00ednh v\u1edbi s\u1ed1 \u0111o di\u1ec7n t\u00edch. a) Th\u1ef1c hi\u1ec7n ph\u00e9p t\u00ednh c\u1ed9ng, tr\u1eeb v\u00e0 chia v\u1edbi c\u00e1c s\u1ed1 \u0111o c\u00f9ng \u0111\u1ea1i l\u01b0\u1ee3ng. b) Th\u1ef1c hi\u1ec7n ph\u00e9p t\u00ednh c\u1ed9ng v\u1edbi c\u00e1c s\u1ed1 \u0111o kh\u00e1c \u0111\u1ea1i l\u01b0\u1ee3ng. \u2013 HS (nh\u00f3m b\u1ed1n) th\u1ea3o lu\u1eadn t\u00ecm c\u00e1ch th\u1ee9c t\u00ednh \u2192 Khi tr\u00ecnh b\u00e0y, HS ch\u1ec9 c\u1ea7n th\u00f4ng b\u00e1o c\u00e1ch l\u00e0m. V\u00ed d\u1ee5: a) Th\u1ef1c hi\u1ec7n gi\u1ed1ng nh\u01b0 khi th\u1ef1c hi\u1ec7n c\u00e1c ph\u00e9p t\u00ednh v\u1edbi c\u00e1c \u0111\u1ea1i l\u01b0\u1ee3ng \u0111\u1ed9 d\u00e0i, kh\u1ed1i l\u01b0\u1ee3ng, dung t\u00edch, \u2026 \t b) \u0110\u1ed5i c\u00e1c s\u1ed1 \u0111o sang c\u00f9ng m\u1ed9t \u0111\u1ea1i l\u01b0\u1ee3ng r\u1ed3i t\u00ednh nh\u01b0 b\u00ecnh th\u01b0\u1eddng (ta ch\u1ec9 th\u1ef1c hi\u1ec7n \u0111\u01b0\u1ee3c c\u00e1c ph\u00e9p t\u00ednh c\u1ed9ng, tr\u1eeb c\u00e1c s\u1ed1 \u0111o khi ch\u00fang c\u00f9ng \u0111\u01a1n v\u1ecb \u0111o). \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb trong nh\u00f3m. \u2013 S\u1eeda b\u00e0i, GV khuy\u1ebfn kh\u00edch c\u00e1c nh\u00f3m HS s\u1eeda b\u00e0i tr\u00ean b\u1ea3ng l\u1edbp (1 nh\u00f3m \/ b\u00e0i to\u00e1n) c\u00f3 gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m \u2192 C\u1ea3 l\u1edbp nh\u1eadn x\u00e9t \u2192 GV gi\u00fap HS ki\u1ec3m tra l\u1ea1i k\u1ebft qu\u1ea3 t\u00ednh.\u00a0 236","V\u00ed d\u1ee5: a) 28 mm2 + 15 mm2 = 43 mm2 \u2192 Em \u0111\u1eb7t t\u00ednh nh\u01b0 ph\u00e9p c\u1ed9ng c\u00e1c s\u1ed1 t\u1ef1 nhi\u00ean, r\u1ed3i \u0111i\u1ec1n k\u1ebft qu\u1ea3 v\u00e0o b\u00e0i to\u00e1n (ho\u1eb7c em c\u1ed9ng nh\u1ea9m, \u2026). \u2026 \t b) \u0110\u1ed5i: 3 cm2 = 300 mm2 \t 3 cm2 + 15 mm2 = 300 mm2 + 15 mm2 = 315 mm2 L\u01b0u \u00fd: HS c\u00f3 th\u1ec3 gi\u1ea3i th\u00edch b\u1eb1ng nhi\u1ec1u c\u00e1ch, n\u1ebfu ph\u00f9 h\u1ee3p th\u00ec c\u00f4ng nh\u1eadn.\u00a0 Ba\u0300i 3: \u2013 HS (nh\u00f3m b\u1ed1n) quan s\u00e1t h\u00ecnh \u1ea3nh trong SGK, so s\u00e1nh di\u1ec7n t\u00edch hai h\u00ecnh \u2192 V\u00e0i nh\u00f3m n\u00eau nh\u1eadn x\u00e9t \u2192 GV ghi nh\u1eadn v\u00e0o g\u00f3c b\u1ea3ng. L\u01b0u \u00fd: Khi so s\u00e1nh di\u1ec7n t\u00edch hai h\u00ecnh, HS c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng m\u1ed9t trong c\u00e1c t\u1eeb: \u201cl\u1edbn h\u01a1n\u201d, \u201cb\u00e9 h\u01a1n\u201d hay \u201cb\u1eb1ng\u201d, kh\u00f4ng b\u1eaft bu\u1ed9c ch\u1ec9 d\u00f9ng m\u1ed9t t\u1eeb \u201cl\u1edbn h\u01a1n\u201d. \u2013 HS \u0111\u1ecdc \u0111\u1ec1 b\u00e0i, nh\u1eadn bi\u1ebft \u0111\u01b0\u1ee3c v\u1ea5n \u0111\u1ec1 c\u1ea7n gi\u1ea3i quy\u1ebft: a) \u01b0\u1edbc l\u01b0\u1ee3ng b) \u0111o v\u00e0 t\u00ednh di\u1ec7n t\u00edch Sau \u0111\u00f3 m\u1edbi so s\u00e1nh. \u2013 HS (nh\u00f3m b\u1ed1n) th\u1ea3o lu\u1eadn t\u00ecm c\u00e1ch l\u00e0m \u2192 Khi tr\u00ecnh b\u00e0y, HS ch\u1ec9 c\u1ea7n th\u00f4ng b\u00e1o c\u00e1ch l\u00e0m. V\u00ed d\u1ee5: a) Di\u1ec7n t\u00edch m\u00f3ng tay ng\u00f3n tr\u1ecf kho\u1ea3ng 1 cm2 \u2192 \u0110\u1eb7t ng\u00f3n tr\u1ecf l\u1ea7n l\u01b0\u1ee3t v\u00e0o h\u00ecnh A v\u00e0 h\u00ecnh B \u0111\u1ec3 \u01b0\u1edbc l\u01b0\u1ee3ng. Hay: D\u1ef1a v\u00e0o h\u00ecnh h\u00ecnh vu\u00f4ng m\u00e0u xanh c\u1ea1nh 1 cm (SGK), ta th\u1ea5y h\u00ecnh A g\u1ed3m \u2026 h\u00ecnh vu\u00f4ng nh\u01b0 th\u1ebf. \t b) \u0110o c\u00e1c c\u1ea1nh r\u1ed3i t\u00ednh di\u1ec7n t\u00edch h\u00ecnh ch\u1eef nh\u1eadt A v\u00e0 h\u00ecnh vu\u00f4ng B. \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb trong nh\u00f3m. \u2013 S\u1eeda b\u00e0i, khuy\u1ebfn kh\u00edch HS k\u1ebft h\u1ee3p thao t\u00e1c tr\u00ean 2 m\u1ea3nh gi\u1ea5y (GV chu\u1ea9n b\u1ecb tr\u01b0\u1edbc). V\u00ed d\u1ee5: a) \u0110\u1eb7t \u0111\u1ea7u ng\u00f3n tay tr\u1ecf v\u00e0o h\u00ecnh \u0111\u1ec3 \u01b0\u1edbc l\u01b0\u1ee3ng: Di\u1ec7n t\u00edch hai h\u00ecnh b\u1eb1ng nhau, b\u1eb1ng kho\u1ea3ng 4 cm2. \t b) \u0110o r\u1ed3i t\u00ednh. \u2022 H\u00ecnh ch\u1eef nh\u1eadt A c\u00f3 chi\u1ec1u d\u00e0i \u0111o \u0111\u01b0\u1ee3c l\u00e0 4 cm v\u00e0 chi\u1ec1u r\u1ed9ng \u0111o \u0111\u01b0\u1ee3c l\u00e0 1 cm \t\t\t 4\u00d71=4 Di\u1ec7n t\u00edch h\u00ecnh ch\u1eef nh\u1eadt A l\u00e0 4 cm2. \u2022 H\u00ecnh vu\u00f4ng B c\u00f3 c\u1ea1nh \u0111o \u0111\u01b0\u1ee3c l\u00e0 2 cm. \t\t\t 2\u00d72=4 Di\u1ec7n t\u00edch h\u00ecnh vu\u00f4ng B l\u00e0 4 cm2. \u2192 Hai h\u00ecnh c\u00f3 di\u1ec7n t\u00edch b\u1eb1ng nhau (ho\u1eb7c: kh\u00f4ng h\u00ecnh n\u00e0o c\u00f3 di\u1ec7n t\u00edch l\u1edbn h\u01a1n). 237","\u2013 GV gi\u00fap HS nh\u1eadn x\u00e9t: \u2022 So s\u00e1nh k\u1ebft qu\u1ea3 t\u00ednh di\u1ec7n t\u00edch hai h\u00ecnh v\u1edbi k\u1ebft qu\u1ea3 \u01b0\u1edbc l\u01b0\u1ee3ng \u2192 b\u1eb1ng nhau, kh\u00f4ng ch\u00eanh l\u1ec7ch. \u2022 So v\u1edbi nh\u1eadn x\u00e9t ban \u0111\u1ea7u c\u1ee7a c\u00e1c nh\u00f3m. L\u01b0u \u00fd\u00a0: Ch\u1ec9 n\u00ean y\u00eau c\u1ea7u HS \u01b0\u1edbc l\u01b0\u1ee3ng di\u1ec7n t\u00edch theo x\u0103ng-ti-m\u00e9t vu\u00f4ng r\u1ed3i chuy\u1ec3n \u0111\u1ed5i \u0111\u01a1n v\u1ecb th\u00e0nh mi-li-m\u00e9t vu\u00f4ng. IV. V\u1eadn d\u1ee5ng, tr\u1ea3i nghi\u1ec7m Luy\u1ec7n t\u1eadp B\u00e0i 1: \u2013 GV gi\u00fap HS x\u00e1c \u0111\u1ecbnh t\u1ea5m \u1ea3nh h\u00ecnh ch\u1eef nh\u1eadt v\u00e0 \u0111\u1ed9 l\u1edbn c\u1ee7a 1 cm2 (h\u00ecnh vu\u00f4ng xanh nh\u1ecf b\u00ean tr\u00e1i trong ph\u1ea7n b\u00e0i h\u1ecdc). \u2013 HS \u0111\u1ecdc \u0111\u1ec1 b\u00e0i, nh\u1eadn bi\u1ebft \u0111\u01b0\u1ee3c v\u1ea5n \u0111\u1ec1 c\u1ea7n gi\u1ea3i quy\u1ebft: a) \u01b0\u1edbc l\u01b0\u1ee3ng b) \u0111o v\u00e0 t\u00ednh di\u1ec7n t\u00edch. \u2013 HS (nh\u00f3m b\u1ed1n) th\u1ea3o lu\u1eadn t\u00ecm c\u00e1ch l\u00e0m. \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb trong nh\u00f3m. \u2013 S\u01b0\u0309a ba\u0300i, HS (v\u00e0i nh\u00f3m) n\u00eau k\u1ebft qu\u1ea3, khuy\u1ebfn kh\u00edch HS gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m. V\u00ed d\u1ee5: a) \u01af\u1edbc l\u01b0\u1ee3ng \t HS n\u00eau k\u1ebft qu\u1ea3, GV ghi nh\u1eadn v\u00e0o g\u00f3c b\u1ea3ng \u2192 T\u1ea5m \u1ea3nh theo chi\u1ec1u r\u1ed9ng kho\u1ea3ng 4 h\u00ecnh vu\u00f4ng v\u00e0 chi\u1ec1u d\u00e0i kho\u1ea3ng 6 h\u00ecnh vu\u00f4ng (ho\u1eb7c \u0111\u1eb7t \u0111\u01b0\u1ee3c 24 ng\u00f3n tay tr\u1ecf v\u00e0o h\u00ecnh, \u2026). L\u01b0u \u00fd: HS c\u00f3 th\u1ec3 gi\u1ea3i th\u00edch b\u1eb1ng nhi\u1ec1u c\u00e1ch, n\u1ebfu ph\u00f9 h\u1ee3p th\u00ec c\u00f4ng nh\u1eadn. \t b) \u0110o r\u1ed3i t\u00ednh \u2022 T\u1ea5m \u1ea3nh c\u00f3 chi\u1ec1u d\u00e0i \u0111o \u0111\u01b0\u1ee3c l\u00e0 6 cm v\u00e0 chi\u1ec1u r\u1ed9ng \u0111o \u0111\u01b0\u1ee3c l\u00e0 4 cm. \t 6 \u00d7 4 = 24 Di\u1ec7n t\u00edch t\u1ea5m \u1ea3nh l\u00e0 24 cm2. \u2013 GV gi\u00fap HS nh\u1eadn x\u00e9t: \u2022 So s\u00e1nh k\u1ebft qu\u1ea3 t\u00ednh v\u1edbi k\u1ebft qu\u1ea3 \u01b0\u1edbc l\u01b0\u1ee3ng. M\u01a1\u0309 r\u00f4\u0323ng: C\u1ea7u V\u00e0ng (\u0110\u00e0 N\u1eb5ng)\u00a0l\u00e0 m\u1ed9t trong nh\u1eefng \u0111i\u1ec3m tham quan n\u1ed5i ti\u1ebfng thu h\u00fat \u0111\u00f4ng \u0111\u1ea3o kh\u00e1ch du l\u1ecbch. C\u00e2y c\u1ea7u g\u00e2y \u1ea5n t\u01b0\u1ee3ng v\u1edbi du kh\u00e1ch nh\u1edd v\u1ebb \u0111\u1eb9p \u0111\u1ed9c l\u1ea1, \u1ea5n t\u01b0\u1ee3ng nh\u01b0 b\u01b0\u1edbc ra t\u1eeb b\u1ee9c tranh. C\u00e2y c\u1ea7u \u201cth\u1ebf k\u1ec9\u201d n\u00e0y n\u1eb1m \u1edf v\u01b0\u1eddn Thi\u00ean Thai, tr\u00ean \u0111\u1ed9 cao 1 414m, trong\u00a0khu du l\u1ecbch B\u00e0 N\u00e0 Hills. C\u1ee5 th\u1ec3 c\u00e2y c\u1ea7u \u0111\u01b0\u1ee3c kh\u1edfi c\u00f4ng x\u00e2y d\u1ef1ng t\u1eeb th\u00e1ng 6\/2017 cho \u0111\u1ebfn th\u00e1ng 6\/2018. Ri\u00eang ph\u1ea7n \u0111\u00f4i b\u00e0n tay kh\u1ed5ng l\u1ed3 \u0111\u01b0\u1ee3c x\u00e2y d\u1ef1ng trong 6 th\u00e1ng, t\u1eeb th\u00e1ng 10\/2017 \u0111\u1ebfn\u00a0th\u00e1ng 4\/2018.\u00a0B\u1eaft \u0111\u1ea7u t\u1eeb th\u00e1ng 6 n\u0103m 2018, C\u1ea7u V\u00e0ng \u0111\u00e3 ch\u00ednh th\u1ee9c m\u1edf c\u1eeda v\u00e0 \u0111i v\u00e0o ho\u1ea1t \u0111\u1ed9ng, m\u1edf c\u1eeda \u0111\u00f3n kh\u00e1ch. B\u00e0i 2: \u2013 HS \u0111\u1ecdc y\u00eau c\u1ea7u. \u2013 HS th\u1ea3o lu\u1eadn (nh\u00f3m b\u1ed1n) t\u00ecm hi\u1ec3u b\u00e0i to\u00e1n, gi\u1ea3i b\u00e0i to\u00e1n. 238","\u2013 HS l\u00e0m c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb v\u1edbi b\u1ea1n. \u2013 S\u1eeda b\u00e0i: GV khuy\u1ebfn kh\u00edch HS gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m. V\u00ed d\u1ee5: C\u00f3 4 nh\u00f3m \u00f4 vu\u00f4ng \u0111\u01b0\u1ee3c c\u1eaft b\u1ecf, m\u1ed7i nh\u00f3m \u00f4 vu\u00f4ng c\u1eaft b\u1ecf 4 \u00f4. Ho\u1eb7c HS t\u00f3m t\u1eaft: 1 nh\u00f3m: 4 \u00f4 vu\u00f4ng. 4 nh\u00f3m: ... \u00f4 vu\u00f4ng. \t C\u1eaft \u0111i ? mm2 \t 4 \u00d7 4 = 16 \u0110\u00e3 c\u1eaft ra 16 \u00f4 vu\u00f4ng. M\u1ed7i \u00f4 vu\u00f4ng c\u00f3 c\u1ea1nh 1 mm \u2192 Di\u1ec7n t\u00edch 1 \u00f4 vu\u00f4ng l\u00e0 1 mm2 \u2192 Di\u1ec7n t\u00edch ph\u1ea7n gi\u1ea5y \u0111\u01b0\u1ee3c c\u1eaft ra l\u00e0 16 mm2. ... L\u01b0u \u00fd: HS c\u00f3 th\u1ec3 gi\u1ea3i th\u00edch b\u1eb1ng nhi\u1ec1u c\u00e1ch, n\u1ebfu ph\u00f9 h\u1ee3p th\u00ec c\u00f4ng nh\u1eadn. Kh\u00e1m ph\u00e1 M\u00f9ng ch\u1ed1ng mu\u1ed7i \u2013 HS \u0111\u1ecdc n\u1ed9i dung trong SGK. \u2013 H\u00ecnh dung 2 mm2 qua h\u00ecnh \u1ea3nh h\u00ecnh vu\u00f4ng m\u00e0u v\u00e0ng c\u00f3 di\u1ec7n t\u00edch 1 mm2 \u1edf ph\u1ea7n C\u00f9ng h\u1ecdc. \u2013 N\u1ebfu kh\u00f4ng ng\u1ee7 m\u00f9ng ch\u1ed1ng mu\u1ed7i th\u00ec \u0111i\u1ec1u g\u00ec x\u1ea3y ra? (Ki\u1ebfn ba khoang c\u1eafn r\u1ea5t \u0111au, mu\u1ed7i truy\u1ec1n b\u1ec7nh s\u1ed1t r\u00e9t, ... \u0111\u1eb7c bi\u1ec7t ph\u1ed5 bi\u1ebfn l\u00e0 b\u1ec7nh s\u1ed1t xu\u1ea5t huy\u1ebft.) Bi\u1ec3u \u0111\u1ed3 v\u1ec1 s\u1ed1 ng\u01b0\u1eddi m\u1eafc b\u1ec7nh s\u1ed1t xu\u1ea5t huy\u1ebft \u2013 HS (nh\u00f3m b\u1ed1n) \u0111\u1ecdc \u0111\u1ec1 b\u00e0i, th\u1ea3o lu\u1eadn, nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u: (l\u00e0m theo l\u1eddi b\u1ea1n Ong) \u0111\u1ecdc s\u1ed1 li\u1ec7u r\u1ed3i so s\u00e1nh s\u1ed1 li\u1ec7u c\u00e1c n\u0103m. \u2022 GV l\u01b0u \u00fd gi\u00fap HS: Tr\u01b0\u1edbc khi \u0111\u1ecdc s\u1ed1 li\u1ec7u v\u00e0 n\u00eau nh\u1eadn x\u00e9t, n\u00f3i kh\u00e1i qu\u00e1t ba \u00fd: Bi\u1ec3u \u0111\u1ed3 n\u00e0y n\u00f3i v\u1ec1 \u0111i\u1ec1u g\u00ec? (HS \u0111\u1ecdc t\u00ean bi\u1ec3u \u0111\u1ed3) D\u00f2ng b\u00ean d\u01b0\u1edbi ghi g\u00ec? C\u1ed9t s\u1ed1 b\u00ean tr\u00e1i ch\u1ec9 g\u00ec? \u2013 HS th\u1ef1c hi\u1ec7n nh\u00f3m \u0111\u00f4i r\u1ed3i chia s\u1ebb trong nh\u00f3m b\u1ed1n. \u2013 S\u01b0\u0309a ba\u0300i, GV c\u00f3 th\u1ec3 treo (ho\u1eb7c chi\u1ebfu) bi\u1ec3u \u0111\u1ed3 l\u00ean, khuy\u1ebfn kh\u00edch HS tr\u00ecnh b\u00e0y k\u1ebft h\u1ee3p ch\u1ec9 v\u00e0o bi\u1ec3u \u0111\u1ed3 (m\u1ed7i nh\u00f3m \/ c\u00e2u). V\u00ed d\u1ee5: \u2013 Bi\u1ec3u \u0111\u1ed3 n\u00e0y n\u00f3i v\u1ec1 \u0111i\u1ec1u g\u00ec? (s\u1ed1 tr\u01b0\u1eddng h\u1ee3p m\u1eafc b\u1ec7nh s\u1ed1t xu\u1ea5t huy\u1ebft trong 6 th\u00e1ng \u1edf m\u1ed7i n\u0103m) \u2013 D\u00f2ng b\u00ean d\u01b0\u1edbi ghi g\u00ec? (n\u0103m) C\u00f3 m\u1ea5y n\u0103m? (6 n\u0103m) \u0110\u00f3 l\u00e0 nh\u1eefng n\u0103m n\u00e0o? (2014; 2015; 2016; 2017; 2018 v\u00e0 2019) \u2013 C\u1ed9t b\u00ean tr\u00e1i ch\u1ec9 g\u00ec? (s\u1ed1 ng\u01b0\u1eddi m\u1eafc b\u1ec7nh) \u2013 \u0110\u1ecdc s\u1ed1 li\u1ec7u tr\u00ean bi\u1ec3u \u0111\u1ed3: 2014 \u2013 11 000 ng\u01b0\u1eddi; 2015 \u2013 13 000 ng\u01b0\u1eddi; \u2026 239","\u2013 So s\u00e1nh s\u1ed1 li\u1ec7u: n\u0103m 2014 c\u00f3 \u00edt ng\u01b0\u1eddi m\u1eafc b\u1ec7nh nh\u1ea5t; n\u0103m 2019 c\u00f3 nhi\u1ec1u ng\u01b0\u1eddi m\u1eafc b\u1ec7nh nh\u1ea5t; n\u0103m 2015 c\u00f3 nhi\u1ec1u ng\u01b0\u1eddi m\u1eafc b\u1ec7nh h\u01a1n n\u0103m 2014 nh\u01b0ng \u00edt ng\u01b0\u1eddi m\u1eafc b\u1ec7nh h\u01a1n nh\u1eefng n\u0103m 2016, 2017, 2018 v\u00e0 2019. \u2026 M\u01a1\u0309 r\u00f4\u0323ng: Nguy\u00ean nh\u00e2n v\u00e0 c\u00e1ch ph\u00f2ng tr\u00e1nh b\u1ec7nh s\u1ed1t xu\u1ea5t huy\u1ebft. \u2013 Nguy\u00ean nh\u00e2n: do mu\u1ed7i v\u1eb1n truy\u1ec1n b\u1ec7nh. \u2013 C\u00e1ch ph\u00f2ng tr\u00e1nh: v\u1ec7 sinh nh\u00e0 c\u1eeda, m\u00f4i tr\u01b0\u1eddng xung quanh, kh\u00f4ng \u0111\u1ec3 ao t\u00f9 n\u01b0\u1edbc \u0111\u1ecdng, di\u1ec7t l\u0103ng qu\u0103ng (b\u1ecd g\u1eady), ng\u1ee7 m\u00f9ng, \u2026 B\u00e0i 58. EM L\u00c0M \u0110\u01af\u1ee2C NH\u1eeeNG G\u00cc? (2 ti\u1ebft) A. Y\u00eau c\u1ea7u c\u1ea7n \u0111\u1ea1t \u2013 HS \u00f4n t\u1eadp v\u00e0 b\u01b0\u1edbc \u0111\u1ea7u h\u1ec7 th\u1ed1ng ho\u00e1 m\u1ed9t s\u1ed1 ki\u1ebfn th\u1ee9c, k\u0129 n\u0103ng v\u1ec1 c\u00e1c ph\u00e9p t\u00ednh \u0111\u00e3 h\u1ecdc; v\u1ec1 m\u1ed9t s\u1ed1 n\u1ed9i dung H\u00ecnh h\u1ecdc v\u00e0 \u0110o l\u01b0\u1eddng; v\u1eadn d\u1ee5ng t\u00ednh nh\u1ea9m, \u00e1p d\u1ee5ng t\u00ednh ch\u1ea5t ph\u00e9p t\u00ednh trong th\u1ef1c h\u00e0nh t\u00ednh to\u00e1n. \u2013 V\u1eadn d\u1ee5ng v\u00e0o gi\u1ea3i quy\u1ebft m\u1ed9t s\u1ed1 v\u1ea5n \u0111\u1ec1 \u0111\u01a1n gi\u1ea3n li\u00ean quan \u0111\u1ebfn t\u00ednh to\u00e1n v\u00e0 \u0111o l\u01b0\u1eddng. \u2013 HS c\u00f3 c\u01a1 h\u1ed9i ph\u00e1t tri\u1ec3n c\u00e1c n\u0103ng l\u1ef1c t\u01b0 duy v\u00e0 l\u1eadp lu\u1eadn to\u00e1n h\u1ecdc, giao ti\u1ebfp to\u00e1n h\u1ecdc, m\u00f4 hi\u0300nh ho\u00e1 toa\u0301n ho\u0323c, gi\u1ea3i quy\u1ebft v\u1ea5n \u0111\u1ec1 to\u00e1n h\u1ecdc v\u00e0 c\u00e1c ph\u1ea9m ch\u1ea5t ch\u0103m ch\u1ec9, tr\u00e1ch nhi\u1ec7m, nh\u00e2n \u00e1i. B. \u0110\u1ed3 d\u00f9ng d\u1ea1y h\u1ecdc GV: C\u00e1c h\u00ecnh \u1ea3nh c\u00f3 trong b\u00e0i (n\u1ebfu c\u1ea7n). HS: \u00ca-ke. C. C\u00e1c ho\u1ea1t \u0111\u1ed9ng d\u1ea1y h\u1ecdc ch\u1ee7 y\u1ebfu I. Kh\u1edfi \u0111\u1ed9ng C\u00f3 th\u1ec3 d\u00f9ng tr\u00f2 ch\u01a1i chuy\u1ec3n t\u1ea3i c\u00e1c n\u1ed9i dung sau. \u2013 Quan h\u1ec7 gi\u1eefa c\u00e1c \u0111\u01a1n v\u1ecb \u0111o kh\u1ed1i l\u01b0\u1ee3ng t\u1ea5n, t\u1ea1, y\u1ebfn, ki-l\u00f4-gam. \u2013 Quan h\u1ec7 gi\u1eefa c\u00e1c \u0111\u01a1n v\u1ecb \u0111o di\u1ec7n t\u00edch \u0111\u00e3 h\u1ecdc. \u2013 Quan h\u1ec7 gi\u1eefa c\u00e1c \u0111\u01a1n v\u1ecb \u0111o dung t\u00edch l\u00edt v\u00e0 mi-li-l\u00edt. II. Th\u1ef1c h\u00e0nh, luy\u1ec7n t\u1eadp B\u00e0i 1: \u2013 Nh\u00f3m hai HS t\u00ecm hi\u1ec3u y\u00eau c\u1ea7u v\u00e0 c\u00e1ch l\u00e0m b\u00e0i. S\u1ed1? \u2192 Chuy\u1ec3n \u0111\u1ed5i \u0111\u01a1n v\u1ecb \u0111o. a) \u0110\u01a1n v\u1ecb \u0111o kh\u1ed1i l\u01b0\u1ee3ng t\u1ea5n, t\u1ea1, y\u1ebfn, ki-l\u00f4-gam \u2192 Hai \u0111\u01a1n v\u1ecb li\u1ec1n nhau g\u1ea5p (k\u00e9m) nhau bao nhi\u00eau l\u1ea7n? \u2192 Nh\u00e2n v\u1edbi 10 (ho\u1eb7c chia cho 10). 240","b) \u0110\u01a1n v\u1ecb \u0111o di\u1ec7n t\u00edch \u2192 Hai \u0111\u01a1n v\u1ecb li\u1ec1n nhau g\u1ea5p (k\u00e9m) nhau bao nhi\u00eau l\u1ea7n? \u2192 Nh\u00e2n v\u1edbi 100 (ho\u1eb7c chia cho 100). \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n, chia s\u1ebb nh\u00f3m \u0111\u00f4i. \u2013 S\u1eeda b\u00e0i, HS th\u00f4ng b\u00e1o k\u1ebft qu\u1ea3 v\u00e0 n\u00f3i c\u00e1ch chuy\u1ec3n \u0111\u1ed5i \u0111\u01a1n v\u1ecb. N\u1ebfu HS l\u00fang t\u00fang, GV c\u00f3 th\u1ec3 gi\u00fap c\u00e1c em (trong tr\u01b0\u1eddng h\u1ee3p HS kh\u00f4ng nh\u1edb m\u1ed1i quan h\u1ec7 gi\u1eefa hai \u0111\u01a1n v\u1ecb kh\u00f4ng li\u1ec1n nhau). Ch\u1eb3ng h\u1ea1n: a) 48\u2009000 kg = .?. t\u1ea5n \u2192 1 t\u1ea5n = .?. kg \u2192 Kh\u00f4ng nh\u1edb! \u2192 t\u1ea5n \u00d710 t\u1ea1 \u00d710 y\u1ebfn \u00d710 kg \u2192 1 t\u1ea5n = 1 \u00d7 10 \u00d7 10 \u00d7 10 kg \u2192 1 t\u1ea5n = 1\u2009000 kg \u2192 1\u2009000 kg = 1 t\u1ea5n \u2192 48\u2009000 kg = 48\u2009000 : 1\u2009000 t\u1ea5n = 48 t\u1ea5n Hay: Coi ngh\u00ecn l\u00e0 \u0111\u01a1n v\u1ecb \u0111\u1ebfm. 1 ngh\u00ecn kg = 1 t\u1ea5n \u2192 48 ngh\u00ecn kg = 48 t\u1ea5n \u2192 48\u2009000 kg = 48 t\u1ea5n. b) 1 m2 = \u2026 mm2 \u2192 m2 \u00d7 100 dm2 \u00d7 100 cm2 \u00d7 100 mm2 B\u00e0i 2: \u2013 HS t\u00ecm hi\u1ec3u y\u00eau c\u1ea7u v\u00e0 th\u1ef1c hi\u1ec7n t\u00ednh to\u00e1n. \u2013 S\u1eeda b\u00e0i, GV khuy\u1ebfn kh\u00edch HS tr\u00ecnh b\u00e0y c\u00e1ch t\u00ednh. L\u01b0u \u00fd: \u0110\u00e2y l\u00e0 b\u00e0i nh\u00e2n v\u1edbi s\u1ed1 c\u00f3 t\u1eadn c\u00f9ng l\u00e0 ch\u1eef s\u1ed1 0, chia hai s\u1ed1 c\u00f3 t\u1eadn c\u00f9ng l\u00e0 ch\u1eef s\u1ed1 0 v\u1edbi l\u1ec7nh: T\u00ednh. HS c\u00f3 th\u1ec3 th\u1ef1c hi\u1ec7n nh\u01b0 sau: C\u00e1ch 1: HS \u0111\u1eb7t t\u00ednh r\u1ed3i t\u00ednh. C\u00e1ch 2: HS th\u1ef1c hi\u1ec7n c\u00e1c thao t\u00e1c t\u00ednh to\u00e1n nh\u01b0 C\u00e1ch 1 nh\u01b0ng kh\u00f4ng \u0111\u1eb7t t\u00ednh. 3\u2009140 \u00d7 90 = 9 nh\u00e2n 4 b\u1eb1ng 36, vi\u1ebft 6 nh\u1edb 3 \t \u2192 3\u2009140 \u00d7 90 = 6 9 nh\u00e2n 1 b\u1eb1ng 9, th\u00eam 3 b\u1eb1ng 12, vi\u1ebft 2, nh\u1edb 1 \u2192 3\u2009140 \u00d7 90 = 26 9 nh\u00e2n 3 b\u1eb1ng 27, th\u00eam 1 b\u1eb1ng 28, vi\u1ebft 28 \t\u2192 3\u2009140 \u00d7 90 = 2826 Vi\u1ebft th\u00eam hai ch\u1eef s\u1ed1 0 v\u00e0o b\u00ean ph\u1ea3i \t\u2192 3\u2009140 \u00d7 90 = 282600 GV l\u01b0u \u00fd HS ki\u1ec3m tra k\u1ebft qu\u1ea3. 241","B\u00e0i 3: \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n. \u2013 S\u1eeda b\u00e0i, HS tr\u00ecnh b\u00e0y c\u00e1ch l\u00e0m. GV h\u1ecfi \u0111\u1ec3 h\u1ec7 th\u1ed1ng ho\u00e1: \u2022 C\u00e1ch \u0111\u1eb7t t\u00ednh? \u2022 C\u00e1ch t\u00ednh. \u2022 \u0110\u1ed1i v\u1edbi ph\u00e9p nh\u00e2n:T\u00ednh t\u1eeb ph\u1ea3i sang tr\u00e1i. \u0110\u1ed1i v\u1edbi ph\u00e9p chia: T\u00ednh t\u1eeb tr\u00e1i sang ph\u1ea3i. L\u01b0u \u00fd: GV c\u1ea7n h\u01b0\u1edbng d\u1eabn cho HS t\u1eadp \u01b0\u1edbc l\u01b0\u1ee3ng th\u01b0\u01a1ng trong m\u1ed7i l\u1ea7n chia. \tCh\u1eb3ng h\u1ea1n: 75 : 37 = ? \tC\u00f3 th\u1ec3 l\u00e0m tr\u00f2n s\u1ed1 nh\u01b0 sau: 80 : 40 = 2. B\u00e0i 4: \u2013 T\u00ecm hi\u1ec3u b\u00e0i: Nh\u00f3m hai HS nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u r\u1ed3i th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n. \u2013 Khi s\u1eeda b\u00e0i, khuy\u1ebfn kh\u00edch HS n\u00f3i c\u00e1ch l\u00e0m. V\u00ed d\u1ee5: T\u00ecm th\u01b0\u01a1ng, s\u1ed1 chia: Th\u1ef1c hi\u1ec7n ph\u00e9p chia. \t T\u00ecm s\u1ed1 b\u1ecb chia: D\u00f9ng quan h\u1ec7 nh\u00e2n, chia hay d\u1ef1a v\u00e0o quy t\u1eafc. \t(N\u1ebfu qu\u00ean quy t\u1eafc th\u00ec vi\u1ebft m\u1ed9t ph\u00e9p t\u00ednh \u0111\u01a1n gi\u1ea3n r\u1ed3i d\u00f9ng suy lu\u1eadn t\u01b0\u01a1ng t\u1ef1.) B\u00e0i 5: \u2013 Nh\u00f3m hai HS t\u00ecm hi\u1ec3u b\u00e0i m\u1eabu, nh\u1eadn bi\u1ebft c\u00e1ch nh\u00e2n. V\u00ed d\u1ee5: 18 \u00d7 50 = (9 \u00d7 2) \u00d7 50 \t = 9 \u00d7 (2 \u00d7 50) \t = 9 \u00d7 100 \t = 900 + V\u00ec sao 18 \u00d7 50 \u0111\u01b0\u1ee3c vi\u1ebft th\u00e0nh (9 \u00d7 2) \u00d7 50? (Do 18 b\u1eb1ng 9 \u00d7 2.) + V\u00ec sao kh\u00f4ng vi\u1ebft 18 b\u1eb1ng 6 \u00d7 3? (V\u00ec 2 \u00d7 50 = 100, nh\u00e2n nh\u1ea9m s\u1ebd thu\u1eadn ti\u1ec7n h\u01a1n.) + V\u00ec sao (9 \u00d7 2) \u00d7 50 \u0111\u01b0\u1ee3c vi\u1ebft th\u00e0nh 9 \u00d7 (2 \u00d7 50)? (Do t\u00ednh ch\u1ea5t k\u1ebft h\u1ee3p c\u1ee7a ph\u00e9p nh\u00e2n.) \u2013 HS th\u1ef1c hi\u1ec7n t\u1eebng ph\u00e9p t\u00ednh v\u00e0o b\u1ea3ng con. \u2013 Khi s\u1eeda b\u00e0i, khuy\u1ebfn kh\u00edch HS gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m. III. V\u1eadn d\u1ee5ng, tr\u1ea3i nghi\u1ec7m B\u00e0i 6: \u2013 HS \u0111\u1ecdc y\u00eau c\u1ea7u. \u2013 HS th\u1ea3o lu\u1eadn (nh\u00f3m b\u1ed1n) t\u00ecm hi\u1ec3u b\u00e0i to\u00e1n, gi\u1ea3i b\u00e0i to\u00e1n. \u2013 HS l\u00e0m c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb v\u1edbi b\u1ea1n. \u2013 S\u1eeda b\u00e0i: GV khuy\u1ebfn kh\u00edch HS gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m. T\u00f3m t\u1eaft\t\t\t\t\t B\u00e0i gi\u1ea3i 80 qu\u1ea3: 8 v\u1ec9\t\t\t\t\t 80 : 8 = 10 120 qu\u1ea3: \u2026 v\u1ec9?\t\t\t\t M\u1ed7i v\u1ec9 c\u00f3 10 qu\u1ea3 tr\u1ee9ng. \t\t\t\t\t \t 120 : 10 = 12 \t\t\t\t\t 120 qu\u1ea3 tr\u1ee9ng c\u00f9ng lo\u1ea1i x\u1ebfp \u0111\u01b0\u1ee3c 12 v\u1ec9. 242","L\u01b0u \u00fd: Khi s\u1eeda b\u00e0i, GV k\u1ebft h\u1ee3p v\u1ea5n \u0111\u00e1p gi\u00fap HS kh\u1eafc s\u00e2u ki\u1ebfn th\u1ee9c. \t B\u00e0i to\u00e1n li\u00ean quan \u0111\u1ebfn r\u00fat v\u1ec1 \u0111\u01a1n v\u1ecb th\u01b0\u1eddng \u0111\u01b0\u1ee3c gi\u1ea3i theo m\u1ea5y b\u01b0\u1edbc? (2 b\u01b0\u1edbc) \t M\u1ed7i b\u01b0\u1edbc, em l\u00e0m g\u00ec? (B\u01b0\u1edbc 1: R\u00fat v\u1ec1 \u0111\u01a1n v\u1ecb \u2192 B\u01b0\u1edbc 2: T\u00ecm k\u1ebft qu\u1ea3 b\u00e0i to\u00e1n) B\u00e0i 7: \u2013 HS (nh\u00f3m \u0111\u00f4i) \u0111\u1ecdc k\u0129 \u0111\u1ec1 b\u00e0i, n\u00f3i ng\u1eafn g\u1ecdn b\u00e0i to\u00e1n: C\u1ea3 g\u1ea1o n\u1ebfp v\u00e0 \u0111\u1eadu xanh: 2 kg. G\u1ea1o n\u1ebfp nhi\u1ec1u h\u01a1n \u0111\u1eadu xanh: 1 kg. M\u1ed7i lo\u1ea1i: \u2026 g? \u2013 HS nh\u1eadn bi\u1ebft: 2 kg l\u00e0 t\u1ed5ng kh\u1ed1i l\u01b0\u1ee3ng hai lo\u1ea1i, 1 kg l\u00e0 hi\u1ec7u kh\u1ed1i l\u01b0\u1ee3ng hai lo\u1ea1i (B\u00e0i to\u00e1n T\u1ed5ng \u2013 Hi\u1ec7u). \u2013 HS l\u00e0m b\u00e0i c\u00e1 nh\u00e2n. B\u00e0i gi\u1ea3i \u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026 C\u00f3 \u2026 g \u0111\u1eadu xanh. \u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026 C\u00f3 \u2026 g g\u1ea1o n\u1ebfp. \u2013 Khi s\u1eeda b\u00e0i, khuy\u1ebfn kh\u00edch nhi\u1ec1u HS tr\u00ecnh b\u00e0y b\u00e0i gi\u1ea3i (c\u00f3 gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m), th\u1eed l\u1ea1i. B\u00e0i 8: \u2013 T\u00ecm hi\u1ec3u b\u00e0i: Nh\u00f3m hai HS \u0111\u1ecdc y\u00eau c\u1ea7u: X\u00e1c \u0111\u1ecbnh \u0111\u00fang hay sai, t\u1ea1i sao sai. \u2013 Khi s\u1eeda b\u00e0i, khuy\u1ebfn kh\u00edch HS n\u00f3i l\u00ed do c\u00e2u d sai. (D\u00f9ng \u00ea-ke ki\u1ec3m tra g\u00f3c.) B\u00e0i 9: \u2013 HS x\u00e1c \u0111\u1ecbnh y\u00eau c\u1ea7u, th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n. \u2013 Khi s\u1eeda b\u00e0i, khuy\u1ebfn kh\u00edch HS gi\u1ea3i th\u00edch t\u1ea1i sao ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00f3. a) D (50 kg \u00d7 50 = 2\u2009500 kg, 2 t\u1ea5n 5 t\u1ea1 = 2\u2009000 kg + 500 kg = 2\u2009500 kg) b) B (20 l = 20 \u00d7 1\u2009000 ml = 20\u2009\u2009000 ml, 500 ml \u00d7 40 = 20\u2009000 ml) c) C (N\u0103m nhu\u1eadn c\u00f3 366 ng\u00e0y, n\u0103m kh\u00f4ng nhu\u1eadn c\u00f3 365 ng\u00e0y.) Th\u1eed th\u00e1ch \u2013 HS (nh\u00f3m b\u1ed1n) nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i v\u00e0 t\u00ecm c\u00e1ch th\u1ef1c hi\u1ec7n. \u2022 Ng\u00e0y 31 th\u00e1ng 12 c\u1ee7a n\u0103m \u0111\u00f3 l\u00e0 th\u1ee9 m\u1ea5y? \u2192 Ng\u00e0y cu\u1ed1i c\u00f9ng c\u1ee7a n\u0103m \u2192 Ng\u00e0y 31 th\u00e1ng 12 l\u00e0 ng\u00e0y th\u1ee9 m\u1ea5y trong tu\u1ea7n cu\u1ed1i c\u00f9ng c\u1ee7a n\u0103m? \u2022 Th\u1ee9 Hai, sau \u0111\u00fang 1 tu\u1ea7n (7 ng\u00e0y) l\u1ea1i l\u00e0 th\u1ee9 Hai. V\u00ed d\u1ee5: Ng\u00e0y 1 th\u00e1ng 1 l\u00e0 th\u1ee9 Hai \u2192 Ng\u00e0y 1 + 1 tu\u1ea7n \u2192 Ng\u00e0y 8 th\u00e1ng 1 c\u0169ng l\u00e0 th\u1ee9 Hai. \t \u2192 Ng\u00e0y 1 + 2 tu\u1ea7n \u2192 c\u0169ng l\u00e0 th\u1ee9 Hai. \t \u2192 Ng\u00e0y 1 + 3 tu\u1ea7n \u2192 c\u0169ng l\u00e0 th\u1ee9 Hai. \t\u2026 243","\u2192 N\u0103m \u0111\u00f3 c\u00f3 bao nhi\u00eau tu\u1ea7n? \u2192 N\u0103m \u0111\u00f3 c\u00f3 365 ng\u00e0y (n\u0103m kh\u00f4ng nhu\u1eadn), 1 tu\u1ea7n c\u00f3 7 ng\u00e0y. \u2013 C\u00e1c nh\u00f3m th\u1ef1c hi\u1ec7n r\u1ed3i tr\u00ecnh b\u00e0y, GV gi\u00fap c\u00e1c em h\u1ec7 th\u1ed1ng l\u1ea1i c\u00e1ch l\u00e0m. (HS n\u00f3i c\u00e1ch l\u00e0m v\u00e0 vi\u1ebft ph\u00e9p t\u00ednh, kh\u00f4ng c\u1ea7n tr\u00ecnh b\u00e0y nh\u01b0 b\u00e0i gi\u1ea3i to\u00e1n c\u00f3 l\u1eddi v\u0103n.) N\u0103m kh\u00f4ng nhu\u1eadn c\u00f3 365 ng\u00e0y. N\u1ebfu kh\u00f4ng t\u00ednh ng\u00e0y \u0111\u1ea7u n\u0103m (ng\u00e0y 1 th\u00e1ng 1) th\u00ec c\u00f2n 364 ng\u00e0y. 364 : 7 = 52 (tu\u1ea7n) \u2192 Ng\u00e0y 1 th\u00e1ng 1 + 52 tu\u1ea7n \u2192 Ng\u00e0y 31 th\u00e1ng 12 c\u1ee7a n\u0103m \u0111\u00f3 c\u0169ng l\u00e0 th\u1ee9 Hai. Ho\u1ea1t \u0111\u1ed9ng th\u1ef1c t\u1ebf HS t\u00ecm h\u00ecnh \u1ea3nh c\u00e1c \u0111\u01b0\u1eddng th\u1eb3ng vu\u00f4ng g\u00f3c, c\u00e1c \u0111\u01b0\u1eddng th\u1eb3ng song song: \u2013 Xung quanh l\u1edbp h\u1ecdc. \u2013 \u1ede nh\u00e0. B\u00e0i 59. TH\u1ef0C H\u00c0NH V\u00c0 TR\u1ea2I NGHI\u1ec6M (2 ti\u1ebft) A. Y\u00eau c\u1ea7u c\u1ea7n \u0111\u1ea1t \u2013 HS \u00f4n t\u1eadp: c\u00e1ch th\u1ef1c hi\u1ec7n c\u00e1c ph\u00e9p t\u00ednh \u0111\u1ec3 t\u00ednh ti\u1ec1n, t\u00ednh kho\u1ea3ng c\u00e1ch gi\u1eefa c\u00e1c ch\u1ed7 ng\u1ed3i trong l\u1edbp. \u2013 V\u1eadn d\u1ee5ng gi\u1ea3i quy\u1ebft c\u00e1c v\u1ea5n \u0111\u1ec1 \u0111\u01a1n gi\u1ea3n c\u1ee7a cu\u1ed9c s\u1ed1ng th\u1ef1c t\u1ebf li\u00ean quan \u0111\u1ebfn vi\u1ec7c t\u00ednh to\u00e1n v\u00e0 th\u1ef1c h\u00e0nh v\u1edbi c\u00e1c \u0111\u1ea1i l\u01b0\u1ee3ng kh\u1ed1i l\u01b0\u1ee3ng, ti\u1ec1n Vi\u1ec7t Nam, g\u00f3p ph\u1ea7n gi\u00e1o d\u1ee5c t\u00e0i ch\u00ednh cho HS; gi\u1ea3i quy\u1ebft v\u1ea5n \u0111\u1ec1 th\u1ef1c ti\u1ec5n li\u00ean quan \u0111\u1ebfn vi\u1ec7c s\u1eafp x\u1ebfp b\u00e0n, gh\u1ebf h\u1ee3p l\u00ed. \u2013 HS c\u00f3 c\u01a1 h\u1ed9i ph\u00e1t tri\u1ec3n c\u00e1c n\u0103ng l\u1ef1c giao ti\u1ebfp to\u00e1n h\u1ecdc; s\u1eed d\u1ee5ng c\u00f4ng c\u1ee5, ph\u01b0\u01a1ng ti\u1ec7n h\u1ecdc to\u00e1n; m\u00f4 h\u00ecnh ho\u00e1 to\u00e1n h\u1ecdc; gi\u1ea3i quy\u1ebft v\u1ea5n \u0111\u1ec1 to\u00e1n h\u1ecdc; t\u01b0 duy v\u00e0 l\u1eadp lu\u1eadn to\u00e1n h\u1ecdc v\u00e0 ph\u1ea9m ch\u1ea5t ch\u0103m ch\u1ec9, tr\u00e1ch nhi\u1ec7m v\u00e0 nh\u00e2n \u00e1i. B. \u0110\u1ed3 d\u00f9ng d\u1ea1y h\u1ecdc GV: M\u1ed7i t\u1ed5 m\u1ed9t b\u1ea3ng ph\u1ee5. HS: Gi\u1ea5y k\u1ebb \u00f4 vu\u00f4ng \u0111\u1ec3 v\u1ebd s\u01a1 \u0111\u1ed3 ch\u1ed7 ng\u1ed3i \u1edf Ho\u1ea1t \u0111\u1ed9ng 2. C. C\u00e1c ho\u1ea1t \u0111\u1ed9ng d\u1ea1y h\u1ecdc ch\u1ee7 y\u1ebfu I. Kh\u1edfi \u0111\u1ed9ng GV c\u00f3 th\u1ec3 cho HS ch\u01a1i \u201cT\u00f4i b\u1ea3o\u201d \u0111\u1ec3 ki\u1ec3m tra d\u1ee5ng c\u1ee5 h\u1ecdc t\u1eadp c\u1ee7a c\u00e1c em. II. Luy\u1ec7n t\u1eadp, th\u1ef1c h\u00e0nh GV c\u00f3 th\u1ec3 cho HS h\u00e1t m\u00faa b\u00e0i \u201cL\u1edbp ch\u00fang m\u00ecnh \u2026\u201d. 244","III. V\u1eadn d\u1ee5ng, tr\u1ea3i nghi\u1ec7m Ho\u1ea1t \u0111\u1ed9ng theo t\u1ed5. Ho\u1ea1t \u0111\u1ed9ng 1. Mua \u0111\u1ed3 \u0103n nh\u1eb9 ph\u1ee5c v\u1ee5 bu\u1ed5i li\u00ean hoan. \u2013 GV giao nhi\u1ec7m v\u1ee5 cho c\u00e1c t\u1ed5 th\u1ea3o lu\u1eadn, t\u00ecm hi\u1ec3u, l\u1eadp k\u1ebf ho\u1ea1ch mua tr\u00e1i c\u00e2y \u0111\u1ec3 li\u00ean hoan. \u2013 \u0110\u1ea1i di\u1ec7n c\u00e1c t\u1ed5 tr\u00ecnh b\u00e0y, chia s\u1ebb cho c\u00e1c b\u1ea1n c\u00f9ng nghe v\u1ec1 k\u1ebf ho\u1ea1ch c\u1ee7a t\u1ed5 m\u00ecnh tr\u01b0\u1edbc l\u1edbp. N\u1ed9i dung c\u00e1c t\u1ed5 tr\u00ecnh b\u00e0y: \t 1. S\u1ed1 ng\u01b0\u1eddi tham d\u1ef1 li\u00ean hoan. \t 2. S\u1ed1 qu\u1ea3 t\u00e1o v\u00e0 s\u1ed1 qu\u1ea3 chu\u1ed1i d\u1ef1 t\u00ednh m\u1ed7i ng\u01b0\u1eddi \u0103n. \t 3. S\u1ed1 qu\u1ea3 t\u00e1o, qu\u1ea3 chu\u1ed1i c\u1ea7n mua. \t 4. S\u1ed1 ki-l\u00f4-gam m\u1ed7i lo\u1ea1i t\u00e1o v\u00e0 chu\u1ed1i c\u1ea7n mua. \t 5. S\u1ed1 ti\u1ec1n mua t\u00e1o. \t 6. S\u1ed1 ti\u1ec1n mua chu\u1ed1i. \t 7. S\u1ed1 ti\u1ec1n mua c\u1ea3 t\u00e1o v\u00e0 chu\u1ed1i. \u2013 S\u1eeda b\u00e0i, GV v\u00e0 HS chia s\u1ebb nh\u1eefng \u0111i\u1ec1u c\u1ea7n l\u01b0u \u00fd: \t + S\u1ed1 ng\u01b0\u1eddi tham d\u1ef1 li\u00ean hoan c\u00f3 t\u00ednh c\u1ea3 GV kh\u00f4ng? \t + S\u1ed1 qu\u1ea3 t\u00e1o v\u00e0 s\u1ed1 qu\u1ea3 chu\u1ed1i d\u1ef1 t\u00ednh c\u00f3 h\u1ee3p l\u00ed kh\u00f4ng? \t + S\u1ed1 ti\u1ec1n mua tr\u00e1i c\u00e2y c\u00f3 v\u01b0\u1ee3t qu\u00e1 400 000 \u0111\u1ed3ng kh\u00f4ng? Ngo\u00e0i ra, GV c\u00f3 th\u1ec3 \u0111\u1ec1 c\u1eadp t\u1edbi nh\u1eefng l\u01b0u \u00fd khi mua b\u00e1n: \t + C\u00e1ch ch\u1ecdn tr\u00e1i c\u00e2y t\u01b0\u01a1i ngon, c\u00e1ch s\u1eafp \u0111\u1eb7t tr\u00e1i c\u00e2y tr\u00e1nh d\u1eadp n\u00e1t khi v\u1eadn chuy\u1ec3n. \t + Gi\u1eef ti\u1ec1n c\u1ea9n th\u1eadn, \u0111\u01b0a ti\u1ec1n cho ng\u01b0\u1eddi b\u00e1n v\u00e0o l\u00fac n\u00e0o, d\u1ef1 t\u00ednh ti\u1ec1n th\u1ed1i l\u1ea1i v\u00e0 ki\u1ec3m \u0111\u1ebfm. \t... \u2192 HS nh\u1eadn bi\u1ebft m\u1ed9t s\u1ed1 k\u0129 n\u0103ng mua b\u00e1n trong cu\u1ed9c s\u1ed1ng, \u0111\u1ed3ng th\u1eddi h\u01b0\u1edbng d\u1eabn HS t\u1eadp t\u00ednh ti\u1ec1n v\u00e0 s\u1eed d\u1ee5ng ti\u1ec1n m\u1ed9t c\u00e1ch h\u1ee3p l\u00ed. Ho\u1ea1t \u0111\u1ed9ng 2. S\u1eafp x\u1ebfp b\u00e0n, gh\u1ebf cho bu\u1ed5i s\u01a1 k\u1ebft. \u2013 GV giao nhi\u1ec7m v\u1ee5 cho c\u00e1c t\u1ed5 th\u1ea3o lu\u1eadn, t\u00ecm hi\u1ec3u c\u00e1ch s\u1eafp x\u1ebfp b\u00e0n gh\u1ebf cho bu\u1ed5i s\u01a1 k\u1ebft. C\u00e1c t\u1ed5 v\u1ebd ph\u00e1c th\u1ea3o c\u00e1ch s\u1eafp x\u1ebfp tr\u00ean gi\u1ea5y k\u1ebb \u00f4 vu\u00f4ng r\u1ed3i v\u1ebd tr\u00ean b\u1ea3ng ph\u1ee5. \u2013 \u0110\u1ea1i di\u1ec7n c\u00e1c t\u1ed5 tr\u00ecnh b\u00e0y, chia s\u1ebb cho c\u00e1c b\u1ea1n c\u00f9ng nghe v\u1ec1 c\u00e1ch s\u1eafp x\u1ebfp c\u1ee7a t\u1ed5 m\u00ecnh. Khuy\u1ebfn kh\u00edch HS n\u00eau l\u00ed do ch\u1ecdn c\u00e1ch s\u1eafp x\u1ebfp \u0111\u00f3. GV h\u01b0\u1edbng d\u1eabn HS khi s\u1eafp x\u1ebfp b\u00e0n, gh\u1ebf c\u1ea7n l\u01b0u \u00fd: \u2022 Ch\u1ed7 ng\u1ed3i c\u1ee7a ng\u01b0\u1eddi tham d\u1ef1 thu\u1eadn l\u1ee3i cho vi\u1ec7c theo d\u00f5i. \u2022 D\u00e0nh nhi\u1ec1u di\u1ec7n t\u00edch s\u00e0n ph\u00f2ng h\u1ecdc cho ho\u1ea1t \u0111\u1ed9ng v\u0103n ngh\u1ec7. \u2022 Ch\u1ed7 ng\u1ed3i b\u1ed1 tr\u00ed thu\u1eadn l\u1ee3i cho vi\u1ec7c di chuy\u1ec3n. \u2013 C\u1ea3 l\u1edbp c\u00f9ng \u0111\u1ed1i chi\u1ebfu v\u1edbi c\u00e1ch l\u00e0m c\u1ee7a c\u00e1c nh\u00f3m \u0111\u1ec3 ch\u1ecdn ra c\u00e1ch s\u1eafp x\u1ebfp ph\u00f9 h\u1ee3p. Sau khi th\u1ed1ng nh\u1ea5t, c\u1ea3 l\u1edbp c\u00f9ng s\u1eafp x\u1ebfp b\u00e0n, gh\u1ebf. 245","KI\u1ec2M TRA GI\u1eeeA H\u1eccC K\u00cc 2 (1 ti\u1ebft) 1. Khoanh v\u00e0o ch\u1eef c\u00e1i tr\u01b0\u1edbc \u00fd tr\u1ea3 l\u1eddi \u0111\u00fang. C\u00e2u 1. S\u1ed1 b\u1ed1n m\u01b0\u01a1i l\u0103m tri\u1ec7u b\u1ed1n tr\u0103m ngh\u00ecn n\u0103m tr\u0103m vi\u1ebft l\u00e0: A. 4\u2009545\t\t B. 45\u2009400\u2009500\t\t C. 45\u2009450\u2009000\t\t D. 45\u2009000\u2009450 C\u00e2u 2. Cho d\u00e3y s\u1ed1: 105 847; 105 000 847; 84 710 500; 84 700 105. \t \u0110\u1ec3 d\u00e3y s\u1ed1 tr\u00ean \u0111\u01b0\u1ee3c s\u1eafp x\u1ebfp theo th\u1ee9 t\u1ef1 t\u1eeb b\u00e9 \u0111\u1ebfn l\u1edbn, em ph\u1ea3i \u0111\u1ed5i ch\u1ed7 hai s\u1ed1 sau: A. 105\u2009000\u2009847 v\u00e0 84\u2009700\u2009105\t\t\t B. 105\u2009847 v\u00e0 84\u2009710\u2009500 C. 105\u2009847 v\u00e0 84\u2009700\u2009105\t\t\t D. 105\u2009000\u2009847 v\u00e0 84\u2009710\u2009500 2. \u0110\u1eb7t t\u00ednh r\u1ed3i t\u00ednh. 7\u2009420 : 68\t \t 20\u2009741\u2009690 \u2013 6\u2009538\u2009477 \t\t\t 3. a) T\u00ednh gi\u00e1 tr\u1ecb bi\u1ec3u th\u1ee9c. \t\t 15\u2009680 + 15 \u00d7 320 b) S\u1ed1? \t \t\t .?. \u2013 5\u2009600\u2009000 = 4\u2009400\u2009000 4. \u0110i\u1ec1n d\u1ea5u ph\u00e9p t\u00ednh th\u00edch h\u1ee3p v\u00e0o . a) 8 8 8 8 = 0 b) 9 3 0 1 = 1 5. T\u00f4 h\u00ecnh b\u00ecnh h\u00e0nh m\u00e0u \u0111\u1ecf, h\u00ecnh thoi m\u00e0u v\u00e0ng. 246","6. S\u1ed1? b) 15 000 mm2 = .?. cm2 a) 8 dm2 = .?. mm2 \t\t\t\t 7. \tNg\u01b0\u1eddi ta chia \u0111\u1ec1u 18 kg mu\u1ed1i v\u00e0o c\u00e1c t\u00fai, m\u1ed7i t\u00fai ch\u1ee9a 75 g mu\u1ed1i. Sau \u0111\u00f3, h\u1ecd x\u1ebfp c\u00e1c t\u00fai mu\u1ed1i v\u00e0o h\u1ed9p, m\u1ed7i h\u1ed9p 12 t\u00fai. H\u1ecfi h\u1ecd c\u1ea7n c\u00f3 bao nhi\u00eau c\u00e1i h\u1ed9p \u0111\u1ec3 \u0111\u1ef1ng h\u1ebft s\u1ed1 t\u00fai mu\u1ed1i \u0111\u00f3? 8. B\u1ea3ng th\u1ed1ng k\u00ea s\u1ed1 \u0111i\u1ec3m 10 m\u00f4n To\u00e1n c\u1ee7a h\u1ecdc sinh l\u1edbp 4C theo c\u00e1c t\u1ed5. T\u1ed5 M\u1ed9t Hai Ba B\u1ed1n S\u1ed1 \u0111i\u1ec3m 10 10 8 7 6 Ng\u01b0\u1eddi ta th\u1ec3 hi\u1ec7n c\u00e1c s\u1ed1 li\u1ec7u tr\u00ean v\u00e0o bi\u1ec3u \u0111\u1ed3 c\u1ed9t b\u00ean d\u01b0\u1edbi. a) Em h\u00e3y vi\u1ebft ch\u1eef v\u00e0 s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 ch\u1ea5m trong bi\u1ec3u \u0111\u1ed3. b) L\u1edbp 4C c\u00f3 t\u1ea5t c\u1ea3 bao nhi\u00eau b\u1ea1n \u0111\u1ea1t \u0111i\u1ec3m 10 m\u00f4n To\u00e1n? (H\u1ecdc sinh) S\u1ed1 h\u1ecdc sinh \u0111\u1ea1t \u0111i\u1ec3m 10 m\u00f4n To\u00e1n 10 8 ........... ........... ........... 6 ........... 4 2 0 ........... ........... ........... ........... (T\u1ed5) 247","4. PH\u00c2N S\u1ed0 B\u00e0i 60. PH\u00c2N S\u1ed0 (2 ti\u1ebft) A. Y\u00eau c\u1ea7u c\u1ea7n \u0111\u1ea1t \u2013 HS nh\u1eadn bi\u1ebft \u0111\u01b0\u1ee3c kh\u00e1i ni\u1ec7m ban \u0111\u1ea7u v\u1ec1 ph\u00e2n s\u1ed1, t\u1eed s\u1ed1, m\u1eabu s\u1ed1; \u0111\u1ecdc, vi\u1ebft \u0111\u01b0\u1ee3c c\u00e1c ph\u00e2n s\u1ed1. \u2013 V\u1eadn d\u1ee5ng gi\u1ea3i quy\u1ebft c\u00e1c v\u1ea5n \u0111\u1ec1 \u0111\u01a1n gi\u1ea3n li\u00ean quan \u0111\u1ebfn kh\u00e1i ni\u1ec7m ph\u00e2n s\u1ed1. \u2013 HS c\u00f3 c\u01a1 h\u1ed9i \u0111\u1ec3 ph\u00e1t tri\u1ec3n c\u00e1c n\u0103ng l\u1ef1c t\u01b0 duy v\u00e0 l\u1eadp lu\u1eadn to\u00e1n h\u1ecdc, giao ti\u1ebfp to\u00e1n h\u1ecdc, m\u00f4 hi\u0300nh ho\u00e1 toa\u0301n ho\u0323c, gi\u1ea3i quy\u1ebft v\u1ea5n \u0111\u1ec1 to\u00e1n h\u1ecdc v\u00e0 c\u00e1c ph\u1ea9m ch\u1ea5t nh\u00e2n \u00e1i, tr\u00e1ch nhi\u1ec7m. B. \u0110\u1ed3 d\u00f9ng d\u1ea1y h\u1ecdc GV: C\u00e1c h\u00ecnh \u1ea3nh c\u00f3 trong b\u00e0i (n\u1ebfu c\u1ea7n). HS: Th\u01b0\u1edbc th\u1eb3ng. C. C\u00e1c ho\u1ea1t \u0111\u1ed9ng d\u1ea1y h\u1ecdc ch\u1ee7 y\u1ebfu I. Kh\u1edfi \u0111\u1ed9ng GV gi\u1edbi thi\u1ec7u: M\u1ed9t t\u1ed5 HS \u0111\u01b0\u1ee3c giao m\u1ed9t m\u1ea3nh \u0111\u1ea5t. \u2013 GV: C\u00e1c b\u1ea1n d\u1ef1 \u0111\u1ecbnh tr\u1ed3ng rau th\u1ebf n\u00e0o tr\u00ean m\u1ea3nh \u0111\u1ea5t \u0111\u00f3? \u2013 HS: Chia m\u1ea3nh \u0111\u1ea5t th\u00e0nh 5 ph\u1ea7n b\u1eb1ng nhau, tr\u1ed3ng rau tr\u00ean 3 ph\u1ea7n. \u2013 GV: Vi\u1ebft s\u1ed1 bi\u1ec3u th\u1ecb ph\u1ea7n tr\u1ed3ng rau tr\u00ean m\u1ea3nh \u0111\u1ea5t. \u2013 HS: 3, 5, \u2026 \u2013 GV: C\u00e1c s\u1ed1 t\u1ef1 nhi\u00ean kh\u00f4ng th\u1ec3 hi\u1ec7n \u0111\u01b0\u1ee3c y\u00eau c\u1ea7u n\u00e0y, c\u1ea7n m\u1ed9t lo\u1ea1i s\u1ed1 m\u1edbi \u2192 Gi\u1edbi thi\u1ec7u b\u00e0i m\u1edbi. II. Kh\u00e1m ph\u00e1, h\u00ecnh th\u00e0nh ki\u1ebfn th\u1ee9c m\u1edbi: Ph\u00e2n s\u1ed1 1. Gi\u1edbi thi\u1ec7u ph\u00e2n s\u1ed1 \u2013 GV d\u00f9ng h\u00ecnh v\u1ebd, gi\u1edbi thi\u1ec7u: Gi\u1ea3 s\u1eed m\u1ea3nh \u0111\u1ea5t h\u00ecnh ch\u1eef nh\u1eadt \u0111\u01b0\u1ee3c chia th\u00e0nh 5 ph\u1ea7n b\u1eb1ng nhau, c\u00e1c b\u1ea1n d\u1ef1 \u0111\u1ecbnh tr\u1ed3ng rau tr\u00ean m\u1ea5y ph\u1ea7n? (3 ph\u1ea7n) \u2013 GV: Ta n\u00f3i \u201cC\u00e1c b\u1ea1n d\u1ef1 \u0111\u1ecbnh tr\u1ed3ng rau tr\u00ean ba ph\u1ea7n n\u0103m m\u1ea3nh \u0111\u1ea5t\u201d. \u2013 GV vi\u1ebft b\u1ea3ng: 3 5 Ba ph\u1ea7n n\u0103m \u2013 GV gi\u1edbi thi\u1ec7u: 3 l\u00e0 m\u1ed9t ph\u00e2n s\u1ed1. 5 \u2013 GV ch\u1ec9 v\u00e0o ph\u00e2n s\u1ed1, HS n\u00f3i: \u201cPh\u00e2n s\u1ed1 ba ph\u1ea7n n\u0103m\u201d. 248","2. Gi\u1edbi thi\u1ec7u t\u1eed s\u1ed1, m\u1eabu s\u1ed1; c\u00e1ch \u0111\u1ecdc, vi\u1ebft ph\u00e2n s\u1ed1 \u2013 GV gi\u1edbi thi\u1ec7u: M\u1ed7i ph\u00e2n s\u1ed1 g\u1ed3m c\u00f3 t\u1eed s\u1ed1 v\u00e0 m\u1eabu s\u1ed1, t\u1eed s\u1ed1 \u1edf tr\u00ean d\u1ea5u g\u1ea1ch ngang, m\u1eabu s\u1ed1 \u1edf d\u01b0\u1edbi d\u1ea5u g\u1ea1ch ngang. \u2013 GV vi\u1ebft b\u1ea3ng. \t\t M\u1eabu s\u1ed1 cho bi\u1ebft m\u1ea3nh \u0111\u1ea5t \u0111\u01b0\u1ee3c chia th\u00e0nh 5 ph\u1ea7n b\u1eb1ng nhau. 3 T\u1eed s\u1ed1 ch\u1ec9 3 ph\u1ea7n b\u1eb1ng nhau nh\u01b0 v\u1eady. \t\t5 \u2013 HS l\u1eb7p l\u1ea1i nhi\u1ec1u l\u1ea7n. \u2013 GV: Khi vi\u1ebft (hay \u0111\u1ecdc) ph\u00e2n s\u1ed1, ta vi\u1ebft (hay \u0111\u1ecdc) t\u1eed s\u1ed1 tr\u01b0\u1edbc, k\u1ebb g\u1ea1ch ngang r\u1ed3i vi\u1ebft (hay \u0111\u1ecdc) m\u1eabu s\u1ed1. 53. \u2013 HS vi\u1ebft r\u1ed3i \u0111\u1ecdc ph\u00e2n s\u1ed1 \u2013 V\u00ed d\u1ee5: H\u00ecnh 1. GV y\u00eau c\u1ea7u HS t\u00ecm hi\u1ec3u theo th\u1ee9 t\u1ef1 sau: \u2022 H\u00ecnh ch\u1eef nh\u1eadt \u0111\u01b0\u1ee3c chia th\u00e0nh m\u1ea5y ph\u1ea7n b\u1eb1ng nhau? \u2022 \u0110\u00e3 t\u00f4 m\u00e0u m\u1ea5y ph\u1ea7n? \u2022 Vi\u1ebft ph\u00e2n s\u1ed1 ch\u1ec9 ph\u1ea7n \u0111\u00e3 t\u00f4 m\u00e0u trong h\u00ecnh ch\u1eef nh\u1eadt. \u2022 \u0110\u1ecdc ph\u00e2n s\u1ed1 v\u1eeba vi\u1ebft. \u2022 Trong ph\u00e2n s\u1ed1 \u0111\u00f3, m\u1eabu s\u1ed1 cho bi\u1ebft g\u00ec, t\u1eed s\u1ed1 cho bi\u1ebft g\u00ec? H\u00ecnh 2. HS th\u1ea3o lu\u1eadn nh\u00f3m r\u1ed3i th\u1ef1c hi\u1ec7n t\u01b0\u01a1ng t\u1ef1 nh\u01b0 H\u00ecnh 1. III. Th\u1ef1c h\u00e0nh, luy\u1ec7n t\u1eadp 1. Th\u1ef1c h\u00e0nh Ba\u0300i 1: \u2013 HS \u0111\u1ecdc y\u00eau c\u1ea7u, nh\u1eadn bi\u1ebft nh\u1eefng vi\u1ec7c c\u1ea7n th\u1ef1c hi\u1ec7n: Quan s\u00e1t h\u00ecnh \u1ea3nh \u2192 Nh\u1eadn bi\u1ebft h\u00ecnh \u0111\u00f3 \u0111\u01b0\u1ee3c chia th\u00e0nh bao nhi\u00eau ph\u1ea7n b\u1eb1ng nhau ho\u1eb7c g\u1ed3m bao nhi\u00eau h\u00ecnh b\u1eb1ng nhau. \t \u2192 C\u00f3 m\u1ea5y ph\u1ea7n (hay m\u1ea5y h\u00ecnh) t\u00f4 m\u00e0u. \t \u2192 Vi\u1ebft ph\u00e2n s\u1ed1, \u0111\u1ecdc ph\u00e2n s\u1ed1. \t \u2192 M\u1eabu s\u1ed1 cho bi\u1ebft g\u00ec, t\u1eed s\u1ed1 cho bi\u1ebft g\u00ec? \u2013 V\u00ed d\u1ee5: H\u00ecnh 2 \u0111\u01b0\u1ee3c chia th\u00e0nh 4 ph\u1ea7n b\u1eb1ng nhau, t\u00f4 m\u00e0u 3 ph\u1ea7n. H\u00ecnh 4 g\u1ed3m 8 c\u00e1i l\u00e1 b\u1eb1ng nhau, t\u00f4 m\u00e0u 3 c\u00e1i l\u00e1. \u2013 S\u1eeda b\u00e0i. 1 3 2 a) 2 4 4 b) 3 8 249"]