SGV TOAN 4

["B\u00e0i 76. T\u00ccM PH\u00c2N S\u1ed0 C\u1ee6A M\u1ed8T S\u1ed0 (2 ti\u1ebft) A. Y\u00eau c\u1ea7u c\u1ea7n \u0111\u1ea1t \u2013 HS th\u1ef1c hi\u1ec7n \u0111\u01b0\u1ee3c vi\u1ec7c t\u00ecm ph\u00e2n s\u1ed1 c\u1ee7a m\u1ed9t s\u1ed1 b\u1eb1ng c\u00e1ch t\u00ednh to\u00e1n. \u2013 V\u1eadn d\u1ee5ng gi\u1ea3i quy\u1ebft c\u00e1c v\u1ea5n \u0111\u1ec1 \u0111\u01a1n gi\u1ea3n v\u1ec1 c\u00e1c \u0111\u1ea1i l\u01b0\u1ee3ng li\u00ean quan \u0111\u1ebfn t\u00ecm ph\u00e2n s\u1ed1 c\u1ee7a m\u1ed9t 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; 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. B. \u0110\u1ed3 d\u00f9ng d\u1ea1y h\u1ecdc GV: C\u00e1c h\u00ecnh \u1ea3nh c\u00f3 trong b\u00e0i (n\u1ebfu c\u1ea7n). C. C\u00e1c ho\u1ea1t \u0111\u1ed9ng d\u1ea1y h\u1ecdc ch\u1ee7 y\u1ebfu I. Kh\u1edfi \u0111\u1ed9ng \u2013 C\u00f3 th\u1ec3 th\u1ef1c hi\u1ec7n b\u1eb1ng c\u00e1ch giao vi\u1ec7c cho c\u00e1c nh\u00f3m GQV\u0110. \u2022 B\u01b0\u1edbc 1: T\u00ecm hi\u1ec3u v\u1ea5n \u0111\u1ec1 2 3 Nh\u1eadn bi\u1ebft v\u1ea5n \u0111\u1ec1 c\u1ea7n gi\u1ea3i quy\u1ebft: T\u00ecm c\u1ee7a 15 qu\u1ea3 c\u00e0 chua. \u2022 B\u01b0\u1edbc 2: L\u1eadp k\u1ebf ho\u1ea1ch N\u00eau \u0111\u01b0\u1ee3c c\u00e1ch th\u1ee9c GQV\u0110: + D\u00f9ng h\u00ecnh \u1ea3nh (v\u1ebd h\u00ecnh). + D\u00f9ng \u00fd ngh\u0129a c\u1ee7a ph\u00e2n s\u1ed1. \u2022 B\u01b0\u1edbc 3: Ti\u1ebfn h\u00e0nh k\u1ebf ho\u1ea1ch HS th\u1ef1c hi\u1ec7n theo c\u00e1ch th\u1ee9c \u1edf b\u01b0\u1edbc 2. Tr\u00ecnh b\u00e0y tr\u01b0\u1edbc l\u1edbp. + V\u1ebd h\u00ecnh: D\u1ef1a v\u00e0o h\u00ecnh v\u1ebd: 2 3 c\u1ee7a 15 qu\u1ea3 c\u00e0 chua l\u00e0 10 qu\u1ea3. + 2 c\u1ee7a 15 qu\u1ea3 c\u00e0 chua t\u1ee9c l\u00e0: 3 15 qu\u1ea3 \u0111\u01b0\u1ee3c chia th\u00e0nh 3 ph\u1ea7n b\u1eb1ng nhau, l\u1ea5y 2 ph\u1ea7n. \u2192 T\u00ecm 1 ph\u1ea7n: 15 : 3 = 5 (qu\u1ea3) \u2192 T\u00ecm 2 ph\u1ea7n: 5 \u00d7 2 = 10 (qu\u1ea3) 2 \u2192 3 c\u1ee7a 15 qu\u1ea3 c\u00e0 chua l\u00e0 10 qu\u1ea3. 300","\u2022 B\u01b0\u1edbc 4: Ki\u1ec3m tra l\u1ea1i 2 ph\u1ea7n \u2192 10 qu\u1ea3. 1 ph\u1ea7n \u2192 5 qu\u1ea3. 3 ph\u1ea7n \u2192 15 qu\u1ea3. \u2013 S\u1eeda b\u00e0i, GV h\u1ec7 th\u1ed1ng c\u00e1ch th\u1ef1c hi\u1ec7n c\u1ee7a c\u00e1c nh\u00f3m. \u2013 GV \u0111\u1eb7t v\u1ea5n \u0111\u1ec1: Ch\u00fang ta \u0111\u00e3 bi\u1ebft c\u00e1ch t\u00ecm ph\u00e2n s\u1ed1 c\u1ee7a m\u1ed9t s\u1ed1 b\u1eb1ng c\u00e1ch d\u1ef1a v\u00e0o h\u00ecnh \u1ea3nh. H\u00f4m nay ta s\u1ebd th\u1ef1c hi\u1ec7n \u0111\u01b0\u1ee3c vi\u1ec7c t\u00ecm ph\u00e2n s\u1ed1 c\u1ee7a m\u1ed9t s\u1ed1 b\u1eb1ng c\u00e1ch t\u00ednh to\u00e1n. II. Kh\u00e1m ph\u00e1, h\u00ecnh th\u00e0nh ki\u1ebfn th\u1ee9c m\u1edbi: T\u00ecm ph\u00e2n s\u1ed1 c\u1ee7a m\u1ed9t s\u1ed1 1.\t V\u00ed d\u1ee5 1 \u2013 HS tr\u1ea3 l\u1eddi c\u00e1c c\u00e2u h\u1ecfi c\u1ee7a GV \u0111\u1ec3 h\u00ecnh th\u00e0nh ki\u1ebfn th\u1ee9c m\u1edbi. 2 + GV vi\u1ebft b\u1ea3ng: T\u00ecm 3 c\u1ee7a 15 + g\u00ec? (15 2 c\u1ee7a 15 c\u00f3 ngh\u0129a l\u00e0 \u0111\u01b0\u1ee3c chia th\u00e0nh 3 ph\u1ea7n b\u1eb1ng nhau, l\u1ea5y 2 ph\u1ea7n.) 3 + Tr\u01b0\u1edbc ti\u00ean, ta t\u00ecm g\u00ec? (L\u1ea5y 15 chia 3 \u0111\u1ec3 t\u00ecm 1 ph\u1ea7n.) + GV vi\u1ebft: 15 : 3 + Sau \u0111\u00f3 t\u00ecm g\u00ec? (L\u1ea5y 1 ph\u1ea7n nh\u00e2n v\u1edbi 2 \u0111\u1ec3 t\u00ecm 2 ph\u1ea7n.) + GV vi\u1ebft ti\u1ebfp: 15 : 3 \u00d7 2 = 10 2 \u2013 Ta ph\u1ea3i t\u00ecm 3 c\u1ee7a 15. D\u1ef1a v\u00e0o bi\u1ec3u th\u1ee9c tr\u00ean, d\u1ef1 \u0111o\u00e1n xem ph\u1ea3i th\u1ef1c hi\u1ec7n ph\u00e9p t\u00ednh g\u00ec gi\u1eefa 15 v\u00e0 2 \u0111\u1ec3 \u0111\u01b0\u1ee3c k\u1ebft qu\u1ea3 l\u00e0 10. 3 HS d\u1ef1 \u0111o\u00e1n \u2192 T\u00ednh to\u00e1n \u2192 K\u1ebft lu\u1eadn. 2 \u2013 \u0110\u1ec3 t\u00ecm 3 c\u1ee7a 15 ta c\u00f3 th\u1ec3 l\u00e0m nh\u01b0 sau; \t\t\t15 \u00d7 2 = 10 (GV vi\u1ebft l\u00ean b\u1ea3ng.) 3 \u2013 Nh\u01b0 v\u1eady, b\u1eb1ng vi\u1ec7c t\u00ednh to\u00e1n, ta c\u00f3 th\u1ec3 t\u00ecm 2 c\u1ee7a 15 b\u1eb1ng nh\u1eefng c\u00e1ch n\u00e0o? 3 + L\u1ea5y 15 chia cho 3 r\u1ed3i nh\u00e2n v\u1edbi 2. 2 + L\u1ea5y 15 nh\u00e2n v\u1edbi 3 . \u2013 H\u1ecfi nhanh, \u0111\u00e1p g\u1ecdn: + 3 c\u1ee7a 12 l\u00e0? (12 \u00d7 3 = 9 hay 12 : 4 \u00d7 3 = 9) 4 4 \u2026 301","2.\t V\u00ed d\u1ee5 2 \u2013 HS (nh\u00f3m b\u1ed1n) th\u1ea3o lu\u1eadn, t\u00ecm c\u00e1ch th\u1ef1c hi\u1ec7n. \u2013 GV c\u00f3 th\u1ec3 g\u1ee3i \u00fd: R\u00fat g\u1ecdn ngay khi c\u00f3 th\u1ec3. \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb v\u1edbi b\u1ea1n trong nh\u00f3m. \u2013 S\u1eeda b\u00e0i, HS tr\u00ecnh b\u00e0y tr\u00ean b\u1ea3ng l\u1edbp, gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m. 5 \t 18 \u00d7 6 = 15 hay 18 : 6 \u00d7 5 = 15 \t HS n\u00f3i: 5 c\u1ee7a 18 l\u00e0 15. 6 III. Th\u1ef1c h\u00e0nh, luy\u1ec7n t\u1eadp 1. Th\u1ef1c h\u00e0nh Ba\u0300i 1: \u2013 HS nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i r\u1ed3i th\u1ef1c hi\u1ec7n (c\u00e1 nh\u00e2n). \u2013 HS c\u00f3 th\u1ec3 th\u1ef1c hi\u1ec7n theo m\u1ed9t trong hai c\u00e1ch tr\u00ean. \u2013 GV l\u01b0u \u00fd HS c\u00e1ch tr\u00ecnh b\u00e0y. V\u00ed d\u1ee5: 1 a) 4 c\u1ee7a 12 l\u00e0: 12 \u00d7 1 =3 (hay 12 : 4 \u00d7 1 = 3) 4 1 HS n\u00f3i: 4 c\u1ee7a 12 l\u00e0 3. Ba\u0300i 2: Th\u1ef1c hi\u1ec7n t\u01b0\u01a1ng t\u1ef1 b\u00e0i Th\u1ef1c h\u00e0nh 1. \u2013 HS l\u00e0m c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb nh\u00f3m b\u1ed1n. \u2013 Khi s\u1eeda b\u00e0i, GV l\u01b0u \u00fd HS c\u00e1ch tr\u00ecnh b\u00e0y c\u00f3 t\u00ean \u0111\u01a1n v\u1ecb. V\u00ed d\u1ee5: 3 = 18 kg (hay 24 kg : 4 \u00d7 3 = 18 kg) 24 kg \u00d7 4 HS n\u00f3i: 3 c\u1ee7a 24 kg l\u00e0 18 kg. 4 \u2026 2. Luy\u1ec7n t\u1eadp B\u00e0i 1: \u2013 HS (nh\u00f3m \u0111\u00f4i) t\u00ecm hi\u1ec3u b\u00e0i. a) GV gi\u00fap HS nh\u1eadn ra b\u00e0i to\u00e1n t\u00ecm ph\u00e2n s\u1ed1 c\u1ee7a m\u1ed9t s\u1ed1. 1 + 7 s\u1ed1 con g\u00e0. S\u1ed1 con g\u00e0 \u1edf \u0111\u00e2y l\u00e0 g\u00ec? (\u0110\u00e0n g\u00e0) 302","+ \u0110\u00e0n g\u00e0 bao nhi\u00eau con? (21 con) 1 + Chuy\u1ec3n c\u00e2u \u201c 7 s\u1ed1 con g\u00e0 l\u00e0 g\u00e0 tr\u1ed1ng\u201d th\u00e0nh c\u00e2u d\u1ea1ng \u201cS\u1ed1 g\u00e0 tr\u1ed1ng b\u1eb1ng \u2026\u201d. (S\u1ed1 g\u00e0 tr\u1ed1ng b\u1eb1ng 1 c\u1ee7a 21 con.) 7 5 b) HS t\u1ef1 n\u00f3i theo c\u00e1ch tr\u00ean. (S\u1ed1 v\u1ec9 tr\u1ee9ng g\u00e0 b\u1eb1ng 2 c\u1ee7a 12 v\u1ec9.) \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n. \u2013 S\u1eeda b\u00e0i, HS th\u00f4ng b\u00e1o k\u1ebft qu\u1ea3, gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m. B\u00e0i 2: \u2013 HS (nh\u00f3m b11\u1ed10nm) \u0111l\u1ecd\u00e0cbya\u00eaounch\u1ea7iu\u00ea,un\u0111h\u1ec1\u1ead-nxib-im\u1ebft\u00e9vti\u1ec7c c\u1ea7n l\u00e0m: S\u1ed1? \u2192 T\u00ecm xem \u2192 GV h\u01b0\u1edbng d\u1eabn HS \u0111\u1ecdc: \u201c 1 c\u1ee7a 1 m\u201d 10 \u2192 \u0110\u1ed5i 1 m = 10 dm 1 \u2192 T\u00ecm 10 c\u1ee7a 10 dm \u2192 L\u01b0u \u00fd l\u00e0m ng\u1eafn g\u1ecdn: \t 10 \u00d7 1 = 10 \u00d71 =1 \t C\u0169ng c\u00f3 th\u1ec3 vi\u1ebft: 1 \u00d710 = 1\u00d710 =1 10 10 10 10 \u2013 HS l\u00e0m c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb nh\u00f3m b\u1ed1n. \u2013 C\u00e1c nh\u00f3m thi \u0111ua s\u1eeda b\u00e0i, gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m. IV. V\u1eadn d\u1ee5ng, tr\u1ea3i nghi\u1ec7m B\u00e0i 3: \u2013 HS (nh\u00f3m b\u1ed1n) \u0111\u1ecdc k\u0129 \u0111\u1ec1 b\u00e0i, t\u00ecm hi\u1ec3u b\u00e0i. GV c\u00f3 th\u1ec3 h\u01b0\u1edbng d\u1eabn HS t\u00f3m t\u1eaft nh\u01b0 sau. + S\u01a1n l\u00e0m m\u1ea5y vi\u1ec7c? (Hai vi\u1ec7c) \u2192 HS vi\u1ebft: Thu d\u1ecdn \u2009Lau nh\u00e0 2 3 + B\u00e0i to\u00e1n cho bi\u1ebft g\u00ec? (C\u1ea3 hai vi\u1ec7c trong 1 gi\u1edd, thu d\u1ecdn m\u1ea5t gi\u1edd.) \u2192 HS vi\u1ebft: Thu d\u1ecdn: 2 gi\u1edd 1 gi\u1edd 3 Lau nh\u00e0 + B\u00e0i to\u00e1n h\u1ecfi g\u00ec? (Lau nh\u00e0 trong bao nhi\u00eau ph\u00fat?) \u2192 HS vi\u1ebft: Thu d\u1ecdn: 2 gi\u1edd 1 gi\u1edd 3 Lau nh\u00e0: \u2026 ph\u00fat? 303","\u2013 D\u1ef1a v\u00e0o t\u00f3m t\u1eaft, HS gi\u1ea3i b\u00e0i to\u00e1n. B\u00e0i gi\u1ea3i 1 \u2212 2 = 1 3 3 S\u01a1n lau nh\u00e0 trong 1 gi\u1edd. 3 1 60 \u00d7 3 = 20 S\u01a1n lau nh\u00e0 trong 20 ph\u00fat. \u2013 S\u1eeda b\u00e0i, HS gi\u1ea3i th\u00edch t\u1eebng b\u01b0\u1edbc l\u00e0m. Ch\u1eb3ng h\u1ea1n: 2 + 1 gi\u1edd g\u1ed3m 3 gi\u1edd v\u00e0 .?. gi\u1edd \u2192 T\u00e1ch \u2192 Tr\u1eeb 1 + 3 c\u1ee7a 1 gi\u1edd l\u00e0 .?. ph\u00fat \u2192 1 c\u1ee7a 60 ph\u00fat l\u00e0 .?. ph\u00fat 3 \u2192 T\u00ecm ph\u00e2n s\u1ed1 c\u1ee7a m\u1ed9t s\u1ed1. B\u00e0i 4: \u2013 HS \u0111\u1ecdc k\u0129 \u0111\u1ec1 b\u00e0i, nh\u1eadn bi\u1ebft c\u00e1i \u0111\u00e3 cho v\u00e0 c\u00e1i ph\u1ea3i t\u00ecm. \u2013 T\u00ecm c\u00e1ch gi\u1ea3i. C\u00f3 1 872 000 \u0111\u1ed3ng, d\u00f9ng 1 200 000 \u0111\u1ed3ng mua qu\u00e0 \u2192 T\u00ecm \u0111\u01b0\u1ee3c s\u1ed1 ti\u1ec1n c\u00f2n l\u1ea1i \u2192 Ti\u1ec1n c\u00f2n l\u1ea1i chi cho hai vi\u1ec7c: Gi\u00fap b\u1ea1n kh\u00f3 kh\u0103n v\u00e0 Li\u00ean hoan 3 (.?. \u0111\u1ed3ng) ( 4 ti\u1ec1n c\u00f2n l\u1ea1i) \u2013 HS gi\u1ea3i (c\u00e1 nh\u00e2n). \t\t B\u00e0i gi\u1ea3i 1\u2009872\u2009000 \u2013 1\u2009200\u2009000 = 672\u2009000 Sau khi mua qu\u00e0, l\u1edbp 4E c\u00f2n l\u1ea1i 672\u2009000 \u0111\u1ed3ng. 3 672\u2009000 \u00d7 4 = 504\u2009000 L\u1edbp 4E d\u00f9ng 504 000 \u0111\u1ed3ng gi\u00fap \u0111\u1ee1 c\u00e1c b\u1ea1n kh\u00f3 kh\u0103n. 672\u2009000 \u2013 504\u2009000 = 168\u2009000 Ti\u1ec1n li\u00ean hoan l\u00e0 168\u2009000 \u0111\u1ed3ng. \u2013 S\u1eeda b\u00e0i theo nh\u00f3m, HS gi\u1ea3i th\u00edch t\u1eebng b\u01b0\u1edbc l\u00e0m. 304","B\u00e0i 77. EM L\u00c0M \u0110\u01af\u1ee2C NH\u1eeeNG G\u00cc? (3 ti\u1ebft) A. Y\u00eau c\u1ea7u c\u1ea7n \u0111\u1ea1t \u2013 HS th\u1ef1c hi\u1ec7n \u0111\u01b0\u1ee3c c\u00e1c n\u1ed9i dung \u00f4n t\u1eadp c\u00e1c ki\u1ebfn th\u1ee9c, k\u0129 n\u0103ng v\u1ec1 ph\u00e2n s\u1ed1 \u0111\u00e3 h\u1ecdc; nh\u1eadn bi\u1ebft s\u1ef1 h\u1ec7 th\u1ed1ng ho\u00e1 c\u1ee7a m\u1ed9t s\u1ed1 ki\u1ebfn th\u1ee9c, k\u0129 n\u0103ng v\u1ec1 ph\u00e2n s\u1ed1. \u2013 V\u1eadn d\u1ee5ng v\u00e0o gi\u1ea3i quy\u1ebft v\u1ea5n \u0111\u1ec1 li\u00ean quan \u0111\u1ebfn ph\u00e2n s\u1ed1 v\u00e0 \u0111\u1ea1i l\u01b0\u1ee3ng, bi\u1ec3u \u0111\u1ed3. \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, nh\u00e2n \u00e1i, trung th\u1ef1c, tr\u00e1ch nhi\u1ec7m. B. \u0110\u1ed3 d\u00f9ng d\u1ea1y h\u1ecdc GV: C\u00e1c h\u00ecnh \u1ea3nh trong b\u00e0i (n\u1ebfu c\u1ea7n). 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 m\u1ed9t tr\u00f2 ch\u01a1i \u0111\u1ec3 chuy\u1ec3n t\u1ea3i c\u00e1c n\u1ed9i dung (ng\u1eafn g\u1ecdn): \u2013 Nh\u1eefng vi\u1ec7c c\u1ea7n l\u00e0m c\u1ee7a b\u00e0i R\u00fat g\u1ecdn ph\u00e2n s\u1ed1. (Chia h\u1ebft c\u1ea3 t\u1eed s\u1ed1 v\u00e0 m\u1eabu s\u1ed1 cho c\u00f9ng m\u1ed9t s\u1ed1 t\u1ef1 nhi\u00ean l\u1edbn h\u01a1n 1 cho t\u1edbi khi \u0111\u01b0\u1ee3c ph\u00e2n s\u1ed1 t\u1ed1i gi\u1ea3n.) \u2013 C\u00e1c c\u00e1ch so s\u00e1nh hai ph\u00e2n s\u1ed1. (Quy \u0111\u1ed3ng m\u1eabu s\u1ed1 l\u00e0 ph\u1ed5 bi\u1ebfn, \u0111\u00f4i khi so s\u00e1nh c\u00e1c ph\u00e2n s\u1ed1 v\u1edbi 1 ho\u1eb7c quy \u0111\u1ed3ng t\u1eed s\u1ed1.) \u2013 C\u1ed9ng (tr\u1eeb) hai ph\u00e2n s\u1ed1. (Quy \u0111\u1ed3ng m\u1eabu s\u1ed1, c\u1ed9ng (tr\u1eeb) t\u1eed s\u1ed1, gi\u1eef nguy\u00ean m\u1eabu s\u1ed1.) \u2013 Nh\u00e2n hai ph\u00e2n s\u1ed1. (T\u1eed s\u1ed1 nh\u00e2n t\u1eed s\u1ed1, m\u1eabu s\u1ed1 nh\u00e2n m\u1eabu s\u1ed1). \u2013 Chia hai ph\u00e2n s\u1ed1. (Ph\u00e2n s\u1ed1 th\u1ee9 nh\u1ea5t nh\u00e2n v\u1edbi ph\u00e2n s\u1ed1 th\u1ee9 hai \u0111\u1ea3o ng\u01b0\u1ee3c.) 2 \u2013 T\u00ecm 3 c\u1ee7a 15. (15 \u00d7 2 ho\u1eb7c 15 : 3 \u00d7 2) 3 II. Th\u1ef1c h\u00e0nh, luy\u1ec7n t\u1eadp B\u00e0i 1: \u2013 HS nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i r\u1ed3i th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n. \u2013 Khi s\u1eeda b\u00e0i, HS gi\u1ea3i th\u00edch t\u1ea1i sao ch\u1ecdn \u00fd \u0111\u00f3. Ch\u1eb3ng h\u1ea1n: H\u00ecnh b\u00ean g\u1ed3m 9 tam gi\u00e1c b\u1eb1ng nhau, t\u00f4 m\u00e0u 5 h\u00ecnh tam gi\u00e1c 5 \u2192 Ph\u00e2n s\u1ed1 ch\u1ec9 ph\u1ea7n \u0111\u01b0\u1ee3c t\u00f4 m\u00e0u trong h\u00ecnh b\u00ean l\u00e0 9 . 305","B\u00e0i 2: \u2013 HS (nh\u00f3m \u0111\u00f4i) nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i: R\u00fat g\u1ecdn ph\u00e2n s\u1ed1. \u2192 Nh\u1eafc l\u1ea1i nh\u1eefng l\u01b0u \u00fd khi l\u00e0m b\u00e0i r\u00fat g\u1ecdn. \u2022 Khi t\u00ecm c\u00e1c s\u1ed1 \u0111\u1ec3 r\u00fat g\u1ecdn, ng\u01b0\u1eddi ta th\u01b0\u1eddng \u0111\u1ec3 \u00fd c\u00e1c tr\u01b0\u1eddng h\u1ee3p \u0111\u1eb7c bi\u1ec7t: S\u1ed1 chia h\u1ebft cho 2? (s\u1ed1 ch\u1eb5n) S\u1ed1 chia h\u1ebft cho 5? (s\u1ed1 c\u00f3 t\u1eadn c\u00f9ng l\u00e0 0 ho\u1eb7c 5) S\u1ed1 chia h\u1ebft cho 10? (s\u1ed1 c\u00f3 t\u1eadn c\u00f9ng l\u00e0 0) C\u00e1c tr\u01b0\u1eddng h\u1ee3p chia h\u1ebft cho 3, 4, 6, 7, 8, 9: V\u1eadn d\u1ee5ng b\u1ea3ng nh\u00e2n, b\u1ea3ng chia. \u2022 C\u00e1ch tr\u00ecnh b\u00e0y. \u2022 K\u1ebft qu\u1ea3 ph\u1ea3i l\u00e0 ph\u00e2n s\u1ed1 t\u1ed1i gi\u1ea3n. \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb nh\u00f3m b\u1ed1n. \u2013 S\u1eeda b\u00e0i theo nh\u00f3m. Y\u00eau c\u1ea7u HS tr\u00ecnh b\u00e0y c\u1ea9n th\u1eadn. V\u00ed d\u1ee5=: 13055 13=055::55 7 21 \t =271 27=1::77 1 3 B\u00e0i 3: \u2013 HS (nh\u00f3m \u0111\u00f4i) nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i, th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n, r\u1ed3i chia s\u1ebb trong nh\u00f3m. \u2013 S\u1eeda b\u00e0i, HS gi\u1ea3i th\u00edch c\u00e1ch ch\u1ecdn (\u0110, S). a) S (21 v\u00e0 49 c\u00f9ng chia h\u1ebft cho 7) 6 1 b) \u0110 (6 : 12 = 12 = 2 do r\u00fat g\u1ecdn cho 6) c) S ( 45 = 3 do r\u00fat g\u1ecdn cho 3 v\u00e0 5) 60 4 (Ho\u1eb7c: 4 c\u1ee7a 60 l\u00e0 60 \u00d7 4 = 80 \u2192 C\u00f3 80 b\u1ea1n n\u1eef \u2192 Kh\u00f4ng \u0111\u00fang, c\u1ea3 \u0111\u1ed9i ch\u1ec9 c\u00f3 60!) 3 3 d) \u0110 3 =3:1=3 (1 3 6 T\u1eeb ph\u00e2n s\u1ed1 1 \u2192 nh\u00e2n c\u1ea3 t\u1eed v\u00e0 m\u1eabu v\u1edbi 2 \u0111\u01b0\u1ee3c 2 \u2192 nh\u00e2n c\u1ea3 t\u1eed v\u00e0 m\u1eabu v\u1edbi 100 \u0111\u01b0\u1ee3c 300 .) 100 B\u00e0i 4: \u2013 HS (nh\u00f3m \u0111\u00f4i) nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i: So s\u00e1nh c\u00e1c ph\u00e2n s\u1ed1. Nh\u1eafc l\u1ea1i c\u00e1ch l\u00e0m: Quy \u0111\u1ed3ng m\u1eabu s\u1ed1 \u2192 So s\u00e1nh t\u1eed s\u1ed1 \u2192 K\u1ebft lu\u1eadn. \u2013 GV l\u01b0u \u00fd HS c\u00e1ch tr\u00ecnh b\u00e0y. HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n. \u2013 S\u1eeda b\u00e0i, HS thi \u0111ua gi\u1eefa c\u00e1c nh\u00f3m. 306","\u2013 GV gi\u00fap HS gi\u1ea3i th\u00edch c\u00e1c b\u01b0\u1edbc l\u00e0m. Ch\u1eb3ng h\u1ea1n: a) 2 v\u00e0 11 (18 chia h\u1ebft cho 3 n\u00ean 18 l\u00e0 m\u1eabu s\u1ed1 chung) 3 8 2 = 2\u00d7 6 = 12 (18 : 3 = 6) 3 3\u00d7 6 18 12 > 11 18 18 V\u1eady 2 > 11 . 3 18 B\u00e0i 5: \u2013 HS (nh\u00f3m b\u1ed1n) nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i: S\u1ed1?. \u2013 Vi\u1ebft s\u1ed1 d\u01b0\u1edbi c\u00e1c v\u1ea1ch c\u1ee7a tia s\u1ed1. \u2013 Th\u1ea3o lu\u1eadn: M\u1ed7i \u0111\u01a1n v\u1ecb (1) hay t\u1eeb 0 t\u1edbi 1 \u0111\u01b0\u1ee3c chia th\u00e0nh m\u1ea5y ph\u1ea7n b\u1eb1ng nhau? \u2192 \u0110\u1ebfm l\u1ea7n l\u01b0\u1ee3t t\u1eebng ph\u1ea7n: 1 ; 2 (t\u1ea1i sao l\u1ea1i l\u00e0 1 ?); 3 ; 4 (t\u1ea1i sao l\u1ea1i l\u00e0 1?) 4 4 2 4 4 Ti\u1ebfp t\u1ee5c: 5 ; 6 (R\u00fat g\u1ecdn b\u1eb1ng bao nhi\u00eau?); 7 ; 8 (t\u1ea1i sao l\u1ea1i l\u00e0 2?) 4 4 4 4 \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb nh\u00f3m b\u1ed1n. \u2013 S\u1eeda b\u00e0i, c\u00e1c nh\u00f3m thi \u0111ua. HS gi\u1ea3i th\u00edch t\u1ea1i sao \u0111i\u1ec1n s\u1ed1 nh\u01b0 v\u1eady. 3 3 7 M\u2192 4 A \u2192 2 T\u2192 4 \u2013 GV h\u01b0\u1edbng d\u1eabn th\u1eed l\u1ea1i. Ch\u1eb3ng h\u1ea1n: M\u1ed7i \u0111\u01a1n v\u1ecb chia th\u00e0nh 4 ph\u1ea7n b\u1eb1ng nhau \u2192 \u0110o\u1ea1n th\u1eb3ng OA g\u1ed3m 6 ph\u1ea7n 6 = 3 \u2192 Ph\u00e2n s\u1ed1 bi\u1ec3u th\u1ecb s\u1ed1 ph\u1ea7n c\u1ee7a \u0111o\u1ea1n th\u1eb3ng OA so v\u1edbi 1 \u0111\u01a1n v\u1ecb l\u00e0 4 2 \u2192 T\u1ea1i \u0111i\u1ec3m A l\u00e0 s\u1ed1 3 . 2 Vui h\u1ecdc B 2 U 5 T\u00ecm \u0111\u01b0\u1eddng \u0111i t\u1eeb A \u0111\u1ebfn E \u2192 D\u1ef1a v\u00e0o b\u00f3ng n\u00f3i 1 1 11 1 7 \u2192 So s\u00e1nh c\u00e1c s\u1ed1 \u0111\u1ec3 t\u00ecm s\u1ed1 l\u1edbn h\u01a1n 4 3 15 10 ho\u1eb7c s\u1ed1 l\u1edbn nh\u1ea5t. \u2013 C\u00e1c nh\u00f3m th\u1ef1c hi\u1ec7n r\u1ed3i tr\u00ecnh b\u00e0y A 3 C 2 T 7 E tr\u01b0\u1edbc l\u1edbp, gi\u1ea3i th\u00edch c\u00e1ch so s\u00e1nh \u1edf t\u1eebng 4 3 5 tr\u01b0\u1eddng h\u1ee3p. \t 1 5 12 9 4 2 6 16 10 5 D 7 S 8 307","B\u00e0i 6: \u2013 HS (nh\u00f3m \u0111\u00f4i) nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u. Th\u1ea3o lu\u1eadn c\u00e1ch l\u00e0m: \u2192 Th\u1ee9 t\u1ef1 th\u1ef1c hi\u1ec7n ph\u00e9p t\u00ednh trong bi\u1ec3u th\u1ee9c. \u2192 Ch\u1ec9 c\u00f3 c\u1ed9ng, tr\u1eeb ho\u1eb7c ch\u1ec9 c\u00f3 nh\u00e2n, chia? C\u00f3 c\u1ea3 c\u1ed9ng, tr\u1eeb, nh\u00e2n, chia? C\u00f3 d\u1ea5u ngo\u1eb7c? \u2013 GV l\u01b0u \u00fd HS c\u00e2n nh\u1eafc khi r\u00fat g\u1ecdn \u0111\u1ec3 thu\u1eadn l\u1ee3i cho b\u01b0\u1edbc ti\u1ebfp theo. HS c\u00f3 th\u1ec3 tr\u00ecnh b\u00e0y nh\u01b0 sau. V\u00ed d\u1ee5: 12 12 6 51 7 25 4 7 255 42 b) 10 + : 5 = 10 + \u00d7 = 7 + 6 10 10 = 13 10 III. V\u1eadn d\u1ee5ng, tr\u1ea3i nghi\u1ec7m B\u00e0i 7: \u2013 HS nh\u1eadn bi\u1ebft c\u1ea7n t\u00ecm th\u00e0nh ph\u1ea7n ch\u01b0a bi\u1ebft trong ph\u00e9p t\u00ednh. \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb nh\u00f3m b\u1ed1n. \u2013 S\u1eeda b\u00e0i, HS gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m. GV l\u01b0u \u00fd HS d\u1ef1a v\u00e0o c\u00e1c tr\u01b0\u1eddng h\u1ee3p nh\u00e2n, chia \u0111\u1eb7c bi\u1ec7t \u0111\u1ec3 th\u1ef1c hi\u1ec7n thu\u1eadn ti\u1ec7n. Ch\u1eb3ng h\u1ea1n: a) 1 nh\u00e2n v\u1edbi s\u1ed1 n\u00e0o \u0111\u1ec3 k\u1ebft qu\u1ea3 v\u1eabn l\u00e0 1 ? 6 6 b) S\u1ed1 n\u00e0o nh\u00e2n v\u1edbi 4 \u0111\u1ec3 b\u1eb1ng 0 ? 7 c) 5 chia cho m\u1ea5y \u0111\u1ec3 k\u1ebft qu\u1ea3 v\u1eabn l\u00e0 5 ? 8 8 B\u00e0i 8: \u2013 HS nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u r\u1ed3i th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n. \u2013 S\u1eeda b\u00e0i, HS gi\u1ea3i th\u00edch t\u1ea1i sao l\u1ea1i t\u00ecm \u0111\u01b0\u1ee3c s\u1ed1 \u0111\u00f3. \uf8eb 1 + 1 + 3 \uf8f6 : 3 = 1 (v\u00ec 64=: 3 23=: 3 1 ) \uf8ed\uf8ec 2 4 4 \uf8f8\uf8f7 2 2 Trung b\u00ecnh m\u1ed7i xe ch\u1edf 1 t\u1ea5n g\u1ea1o. 2 308","B\u00e0i 9: \u2013 HS \u0111\u1ecdc k\u0129 b\u00e0i, ph\u00e2n bi\u1ec7t c\u00e1i ph\u1ea3i t\u00ecm v\u00e0 c\u00e1i \u0111\u00e3 cho. \u2192 Nh\u1eadn d\u1ea1ng b\u00e0i to\u00e1n \u201cT\u1ed5ng \u2013 Hi\u1ec7u\u201d. \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n, s\u1eeda b\u00e0i theo nh\u00f3m. B\u00e0i gi\u1ea3i (7 \u2013 2) : 2 = 5 2 5 Con b\u00f2 v\u00e0ng c\u00e2n n\u1eb7ng 2 t\u1ea1. 5 + 2 = 9 2 2 9 Con b\u00f2 s\u1eefa c\u00e2n n\u1eb7ng 2 t\u1ea1. \u2013 Khuy\u1ebfn kh\u00edch HS th\u1eed l\u1ea1i. C\u1ea3 hai con: 5 t\u1ea1 + 9 t\u1ea1 = 14 t\u1ea1 = 7 t\u1ea1. 2 2 2 B\u00f2 s\u1eefa n\u1eb7ng h\u01a1n b\u00f2 v\u00e0ng: 9 t\u1ea1 \u2013 5 t\u1ea1 = 4 t\u1ea1 = 2 t\u1ea1. 2 2 2 B\u00e0i 10: \u2013 HS (nh\u00f3m b\u1ed1n) t\u00ecm hi\u1ec3u b\u00e0i. M\u00f4 t\u1ea3 bi\u1ec3u \u0111\u1ed3. Bi\u1ec3u \u0111\u1ed3 n\u00f3i v\u1ec1 c\u00e1i g\u00ec? (c\u00e1c m\u00f4n th\u1ec3 thao HS \u0111\u0103ng k\u00ed) \u2192 M\u1ea5y m\u00f4n, \u0111\u00f3 l\u00e0 nh\u1eefng m\u00f4n n\u00e0o? \u2192 Chi\u1ec1u cao m\u1ed7i c\u1ed9t m\u00e0u bi\u1ec3u th\u1ecb \u0111i\u1ec1u g\u00ec? (ph\u1ea7n HS \u0111\u0103ng k\u00ed m\u1ed7i m\u00f4n so v\u1edbi HS c\u1ea3 l\u1edbp) \u2192 HS c\u1ea3 l\u1edbp \u0111\u01b0\u1ee3c chia th\u00e0nh bao nhi\u00eau ph\u1ea7n b\u1eb1ng nhau? (8 ph\u1ea7n) \u2192 Vi\u1ebft ph\u00e2n s\u1ed1 t\u1ed1i gi\u1ea3n bi\u1ec3u th\u1ecb ph\u1ea7n HS \u0111\u0103ng k\u00ed m\u1ed7i m\u00f4n. \u2013 HS th\u1ef1c hi\u1ec7n (nh\u00f3m \u0111\u00f4i), chia s\u1ebb nh\u00f3m b\u1ed1n. \u2013 S\u1eeda b\u00e0i, c\u00e1c nh\u00f3m tr\u00ecnh b\u00e0y v\u00e0 gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m. a) B\u00f3ng \u0111\u00e1 1 . ( 2 = 1 ) 5 10 5 B\u00f3ng r\u1ed5 2 . ( 4 = 2 ) 5 10 5 C\u1ea7u l\u00f4ng 3 . 10 B\u00f3ng b\u00e0n 1 . 10 309","b) S\u1eafp x\u1ebfp c\u00e1c ph\u00e2n s\u1ed1 theo th\u1ee9 t\u1ef1 t\u1eeb l\u1edbn \u0111\u1ebfn b\u00e9: 2 3 1 1 1 2 2 4 5 ; 10 ; 5 ; 10 (do 5 = 10 , 5 = 10 ) \u2192 C\u00e1c m\u00f4n th\u1ec3 thao m\u00e0 HS \u0111\u0103ng k\u00ed theo th\u1ee9 t\u1ef1 t\u1eeb nhi\u1ec1u \u0111\u1ebfn \u00edt: B\u00f3ng r\u1ed5, c\u1ea7u l\u00f4ng, b\u00f3ng \u0111\u00e1, b\u00f3ng b\u00e0n. c) T\u1ed5ng c\u00e1c ph\u00e2n s\u1ed1: 2 + 3 + 1 + 1 5 10 5 10 = 4 + 3 + 2 + 1 10 10 10 10 = 10 10 =1 Ho\u1ea1t \u0111\u1ed9ng th\u1ef1c t\u1ebf \u2013 HS th\u1ea3o lu\u1eadn nh\u00f3m, th\u1ef1c h\u1ec7n v\u00e0 tr\u00ecnh b\u00e0y tr\u01b0\u1edbc l\u1edbp. \u2013 S\u1eeda b\u00e0i, GV gi\u00fap c\u00e1c em di\u1ec5n \u0111\u1ea1t. 5 12 a) Ph\u00e2n s\u1ed1 t\u1ed1i gi\u1ea3n ch\u1ec9 s\u1ed1 truy\u1ec7n thi\u1ebfu nhi trong t\u1ee7 s\u00e1ch: =17850 17=850::55 15 36 =1356 13=56 :: 33 5 12 b) 1 = 3 , 5 > 3 n\u00ean ta n\u00f3i: \u201cH\u01a1n 1 s\u1ed1 s\u00e1ch trong t\u1ee7 l\u00e0 truy\u1ec7n thi\u1ebfu nhi\u201d. 4 12 12 12 4 1 = 6 , 5 < 6 n\u00ean ta n\u00f3i: \u201cS\u1ed1 truy\u1ec7n thi\u1ebfu nhi ch\u01b0a t\u1edbi 1 s\u1ed1 s\u00e1ch trong t\u1ee7\u201d. 2 12 12 12 2 C\u0169ng c\u00f3 th\u1ec3 gi\u1ea3i th\u00edch theo c\u00e1ch kh\u00e1c: + 1 s\u1ed1 s\u00e1ch trong t\u1ee7 l\u00e0 45 quy\u1ec3n (180 \u00d7 1 = 45) 4 4 S\u1ed1 truy\u1ec7n thi\u1ebfu nhi l\u00e0 75 quy\u1ec3n. 1 Do 75 > 45 n\u00ean ta n\u00f3i: \u201cH\u01a1n 4 s\u1ed1 s\u00e1ch trong t\u1ee7 l\u00e0 truy\u1ec7n thi\u1ebfu nhi\u201d. + 1 s\u1ed1 s\u00e1ch trong t\u1ee7 l\u00e0 90 quy\u1ec3n (180 \u00d7 1 = 90) 2 2 Do 75 < 90 n\u00ean ta n\u00f3i: \u201cS\u1ed1 truy\u1ec7n thi\u1ebfu nhi ch\u01b0a t\u1edbi 1 s\u1ed1 s\u00e1ch trong t\u1ee7\u201d. 2 310","B\u00e0i 78. \u00d4N T\u1eacP CU\u1ed0I N\u0102M (11 ti\u1ebft) A. Y\u00eau c\u1ea7u c\u1ea7n \u0111\u1ea1t \u2013 HS th\u1ef1c hi\u1ec7n \u0111\u01b0\u1ee3c c\u00e1c n\u1ed9i dung \u00f4n t\u1eadp c\u00e1c ki\u1ebfn th\u1ee9c, k\u0129 n\u0103ng v\u1ec1 c\u00e1c m\u1ea1ch ki\u1ebfn th\u1ee9c \u0111\u00e3 h\u1ecdc: S\u1ed1 v\u00e0 Ph\u00e9p t\u00ednh; H\u00ecnh h\u1ecdc v\u00e0 \u0110o l\u01b0\u1eddng; M\u1ed9t s\u1ed1 y\u1ebfu t\u1ed1 Th\u1ed1ng k\u00ea v\u00e0 X\u00e1c su\u1ea5t; nh\u1eadn bi\u1ebft s\u1ef1 h\u1ec7 th\u1ed1ng ho\u00e1 c\u1ee7a m\u1ed9t s\u1ed1 ki\u1ebfn th\u1ee9c, k\u0129 n\u0103ng. \u2013 V\u1eadn d\u1ee5ng v\u00e0o gi\u1ea3i quy\u1ebft v\u1ea5n \u0111\u1ec1 \u0111\u01a1n gi\u1ea3n c\u1ee7a cu\u1ed9c s\u1ed1ng th\u1ef1c t\u1ebf. \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, s\u1eed d\u1ee5ng c\u00f4ng c\u1ee5 v\u00e0 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, nh\u00e2n \u00e1i, trung th\u1ef1c, tr\u00e1ch nhi\u1ec7m, y\u00eau n\u01b0\u1edbc. B. \u0110\u1ed3 d\u00f9ng d\u1ea1y h\u1ecdc GV: Th\u01b0\u1edbc th\u1eb3ng, \u00ea-ke, c\u00e1c kh\u1ed1i l\u1eadp ph\u01b0\u01a1ng d\u00f9ng cho Luy\u1ec7n t\u1eadp 3 (\u00d4n t\u1eadp H\u00ecnh h\u1ecdc v\u00e0 \u0110o l\u01b0\u1eddng), th\u01b0\u1edbc \u0111o g\u00f3c; c\u00e1c h\u00ecnh \u1ea3nh c\u00f3 trong b\u00e0i (n\u1ebfu c\u1ea7n). HS: Th\u01b0\u1edbc th\u1eb3ng, \u00ea-ke, th\u01b0\u1edbc \u0111o g\u00f3c, c\u00e1c kh\u1ed1i l\u1eadp ph\u01b0\u01a1ng d\u00f9ng cho Luy\u1ec7n t\u1eadp 3 (\u00d4n t\u1eadp H\u00ecnh h\u1ecdc v\u00e0 \u0110o l\u01b0\u1eddng), c\u00e1c th\u1ebb s\u1ed1 d\u00f9ng cho Luy\u1ec7n t\u1eadp 2 (\u00d4n t\u1eadp m\u1ed9t s\u1ed1 y\u1ebfu t\u1ed1 Th\u1ed1ng k\u00ea v\u00e0 X\u00e1c su\u1ea5t). C. C\u00e1c ho\u1ea1t \u0111\u1ed9ng d\u1ea1y h\u1ecdc ch\u1ee7 y\u1ebfu \u00d4N T\u1eacP S\u1ed0 T\u1ef0 NHI\u00caN V\u00c0 C\u00c1C PH\u00c9P T\u00cdNH (4 ti\u1ebft) I. Kh\u1edfi \u0111\u1ed9ng C\u00f3 th\u1ec3 d\u00f9ng m\u1ed9t tr\u00f2 ch\u01a1i chuy\u1ec3n t\u1ea3i c\u00e1c n\u1ed9i dung (ng\u1eafn g\u1ecdn): \u2013 N\u00eau c\u00e1c h\u00e0ng c\u1ee7a c\u00e1c l\u1edbp: L\u1edbp tri\u1ec7u, l\u1edbp ngh\u00ecn, l\u1edbp \u0111\u01a1n v\u1ecb. \u2013 H\u00e0ng cao nh\u1ea5t c\u1ee7a m\u1ed9t s\u1ed1 l\u00e0 Ch\u1ee5c tri\u1ec7u \u2192 S\u1ed1 \u0111\u00f3 c\u00f3 m\u1ea5y ch\u1eef s\u1ed1? \u2013 D\u00e3y s\u1ed1 t\u1ef1 nhi\u00ean (s\u1eafp x\u1ebfp, hai s\u1ed1 li\u1ec1n nhau, s\u1ed1 b\u00e9 nh\u1ea5t, c\u00f3 s\u1ed1 l\u1edbn nh\u1ea5t kh\u00f4ng?, \u2026). \u2013 So s\u00e1nh s\u1ed1 t\u1ef1 nhi\u00ean. \u2013 C\u00e1c ph\u00e9p t\u00ednh v\u1edbi s\u1ed1 t\u1ef1 nhi\u00ean. \u2013 Ph\u00e2n s\u1ed1 c\u00f3 ph\u1ea3i l\u00e0 m\u1ed9t s\u1ed1 kh\u00f4ng? M\u1eabu s\u1ed1 bi\u1ec3u th\u1ecb g\u00ec, t\u1eed s\u1ed1 bi\u1ec3u th\u1ecb g\u00ec? Cho v\u00ed d\u1ee5. (Ph\u00e2n s\u1ed1 c\u0169ng l\u00e0 m\u1ed9t s\u1ed1. 3 L\u1ea5y 5 c\u00e1i b\u00e1nh c\u00f3 ngh\u0129a l\u00e0: c\u00e1i b\u00e1nh \u0111\u01b0\u1ee3c chia th\u00e0nh 5 ph\u1ea7n b\u1eb1ng nhau, l\u1ea5y \u0111i 3 ph\u1ea7n) \u2026 II. Th\u1ef1c h\u00e0nh, luy\u1ec7n t\u1eadp B\u00e0i 1: \u2013 HS (nh\u00f3m \u0111\u00f4i) t\u00ecm hi\u1ec3u m\u1eabu. B\u1ea3ng g\u1ed3m m\u1ea5y c\u1ed9t, n\u1ed9i dung m\u1ed7i c\u1ed9t l\u00e0 g\u00ec? B\u1ea3ng g\u1ed3m m\u1ea5y h\u00e0ng, m\u1ed7i h\u00e0ng l\u00e0 m\u1ed9t c\u00e2u. \u1ede m\u1ed7i h\u00e0ng, ng\u01b0\u1eddi ta cho bi\u1ebft m\u1ed9t n\u1ed9i dung \u2192 Th\u1ef1c hi\u1ec7n hai n\u1ed9i dung c\u00f2n l\u1ea1i. 311","\u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb nh\u00f3m \u0111\u00f4i. \u2013 Khi s\u1eeda b\u00e0i, n\u1ebfu c\u1ea7n th\u00ec y\u00eau c\u1ea7u HS gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m. a) \u0110\u1ecdc s\u1ed1 \u2192 Vi\u1ebft s\u1ed1 \u2192 Vi\u1ebft s\u1ed1 th\u00e0nh t\u1ed5ng. b) Vi\u1ebft s\u1ed1 \u2192 \u0110\u1ecdc s\u1ed1 \u2192 Vi\u1ebft s\u1ed1 th\u00e0nh t\u1ed5ng. \u1ede c\u00e2u n\u00e0y, HS c\u00f3 th\u1ec3 \u0111\u1ecdc: \u2026 ch\u00edn tr\u0103m l\u1ebb m\u1ed9t ngh\u00ecn \u2026 Nh\u01b0ng GV n\u00ean \u0111\u1ecdc: \u2026 ch\u00edn tr\u0103m linh m\u1ed9t ngh\u00ecn \u2026 c) Vi\u1ebft s\u1ed1 th\u00e0nh t\u1ed5ng \u2192 Vi\u1ebft s\u1ed1 \u2192 \u0110\u1ecdc s\u1ed1. 7 000 000 + 20 000 + 300 + 1 \u2192 S\u1ed1 ph\u1ea3i vi\u1ebft c\u00f3 b\u1ea3y ch\u1eef s\u1ed1: . \u2026 \u2026 Ch\u1eef s\u1ed1 7 \u1edf h\u00e0ng tri\u1ec7u: \t7 \u2026 \u2026 Ch\u1eef s\u1ed1 2 \u1edf h\u00e0ng ch\u1ee5c ngh\u00ecn: 7 .2. \u2026 Ch\u1eef s\u1ed1 3 \u1edf h\u00e0ng tr\u0103m: \t 7 .2. 3.. Ch\u1eef s\u1ed1 1 \u1edf h\u00e0ng \u0111\u01a1n v\u1ecb, \t 7 .2. 3.1 C\u00e1c ch\u1eef s\u1ed1 c\u00f2n l\u1ea1i l\u00e0 0. \t 7 020 301 \u2192 \u0110\u1ecdc s\u1ed1: B\u1ea3y tri\u1ec7u kh\u00f4ng tr\u0103m hai m\u01b0\u01a1i ngh\u00ecn ba tr\u0103m linh m\u1ed9t. B\u00e0i 2: \u2013 HS (nh\u00f3m \u0111\u00f4i) nh\u1eadn bi\u1ebft 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, HS tr\u00ecnh b\u00e0y v\u00e0 gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m (n\u1ebfu c\u1ea7n). \t\t 668\u2009619\u2009840 ng\u01b0\u1eddi a) D\u00e2n s\u1ed1 khu v\u1ef1c \u0110\u00f4ng Nam \u00c1 n\u0103m 2020 l\u00e0: S\u00e1u tr\u0103m s\u00e1u m\u01b0\u01a1i t\u00e1m tri\u1ec7u s\u00e1u tr\u0103m m\u01b0\u1eddi ch\u00edn ngh\u00ecn t\u00e1m tr\u0103m b\u1ed1n m\u01b0\u01a1i ng\u01b0\u1eddi. b) Trong s\u1ed1 668\u2009619\u2009840: L\u1edbp tri\u1ec7u g\u1ed3m c\u00e1c ch\u1eef s\u1ed1: 6, 6 v\u00e0 8. Ch\u1eef s\u1ed1 4 thu\u1ed9c h\u00e0ng ch\u1ee5c, l\u1edbp \u0111\u01a1n v\u1ecb. C\u00e1c ch\u1eef s\u1ed1 8 k\u1ec3 t\u1eeb tr\u00e1i sang ph\u1ea3i l\u1ea7n l\u01b0\u1ee3t c\u00f3 gi\u00e1 tr\u1ecb l\u00e0: \t 8 tri\u1ec7u, 8 tr\u0103m (hay 8\u2009000\u2009000, 800). c) L\u00e0m tr\u00f2n s\u1ed1 668\u2009619\u2009840 \u0111\u1ebfn h\u00e0ng ngh\u00ecn th\u00ec \u0111\u01b0\u1ee3c s\u1ed1 668\u2009620\u2009000. (X\u00e9t ch\u1eef s\u1ed1 \u1edf h\u00e0ng tr\u0103m l\u00e0 8 \u2192 Th\u00eam 1 v\u00e0o h\u00e0ng ngh\u00ecn \u0111\u01b0\u1ee3c 10 ngh\u00ecn \u2192 Vi\u1ebft 0 \u1edf h\u00e0ng ngh\u00ecn, nh\u1edb 1 sang h\u00e0ng ch\u1ee5c ngh\u00ecn \u0111\u01b0\u1ee3c 2 ch\u1ee5c ngh\u00ecn.) B\u00e0i 3: \u2013 HS nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i: T\u00ecm c\u00e2u \u0111\u00fang, c\u00e2u sai. \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 (n\u1ebfu c\u1ea7n). a) \u0110 b) \u0110 (N\u1ebfu c\u00f3 s\u1ed1 th\u1eadt l\u1edbn \u2192 Th\u00eam 1 v\u00e0o s\u1ed1 \u0111\u00f3 s\u1ebd \u0111\u01b0\u1ee3c s\u1ed1 l\u1edbn h\u01a1n.) c) S (90 v\u00e0 110 l\u00e0 hai s\u1ed1 tr\u00f2n ch\u1ee5c, th\u1ef1c ra \u0111\u00e2y l\u00e0 ba s\u1ed1 tr\u00f2n ch\u1ee5c.) 312","Vui h\u1ecdc 34 35 75 16 18 36 71 73 74 20 \u2013 Ho\u1ea1t \u0111\u1ed9ng nh\u00f3m. 54 56 57 47 62 \u2013 Nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i: 10 9 49 99 63 12 51 98 95 100 T\u00ecm c\u00e0 r\u1ed1t gi\u00fap th\u1ecf. \u2192 X\u00e1c \u0111\u1ecbnh \u0111i\u1ec3m xu\u1ea5t ph\u00e1t v\u00e0 \u0111i\u1ec3m k\u1ebft th\u00fac. \u2192 C\u00e1ch \u0111i: Theo b\u00f3ng n\u00f3i c\u1ee7a th\u1ecf m\u1eb9. Theo c\u00e1c nh\u00f3m: + Ba s\u1ed1 t\u1ef1 nhi\u00ean li\u00ean ti\u1ebfp + Ba s\u1ed1 ch\u1eb5n li\u00ean ti\u1ebfp (Cho v\u00ed d\u1ee5?) + Ba s\u1ed1 l\u1ebb li\u00ean ti\u1ebfp (Cho v\u00ed d\u1ee5?) \u2013 Nh\u00f3m n\u00e0o l\u00e0m \u0111\u00fang v\u00e0 nhanh nh\u1ea5t th\u00ec th\u1eafng. Th\u1eed th\u00e1ch \u2013 Ho\u1ea1t \u0111\u1ed9ng nh\u00f3m. \u2013 Nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i: a) S\u1ed1 v\u1edf c\u1ee7a H\u00e0 l\u00e0 s\u1ed1 ch\u1eb5n hay l\u1ebb? V\u00ec sao? b) S\u1ed1 v\u1edf H\u00e0 t\u1eb7ng b\u1ea1n l\u00e0 s\u1ed1 ch\u1eb5n hay l\u1ebb? \u2013 Ho\u1ea1t \u0111\u1ed9ng nh\u00f3m. \u2013 C\u00e1c nh\u00f3m nh\u1eadn bi\u1ebft c\u00e1c th\u00f4ng tin c\u1ea7n thi\u1ebft v\u00e0 c\u00e2u h\u1ecfi c\u1ee7a b\u00e0i. Th\u1ea3o lu\u1eadn \u0111\u1ec3 GQV\u0110. 1 2 s\u1ed1 v\u1edf = s\u1ed1 v\u1edf : 2 \u2192 Nh\u1eefng s\u1ed1 n\u00e0o chia h\u1ebft cho 2? S\u1ed1 ch\u1eb5n hay s\u1ed1 l\u1ebb? V\u00ec sao? \u2192 Th\u01b0\u01a1ng c\u1ee7a b\u00e0i to\u00e1n chia cho 2 c\u00f3 th\u1ec3 l\u00e0 nh\u1eefng s\u1ed1 n\u00e0o? S\u1ed1 ch\u1eb5n hay s\u1ed1 l\u1ebb? V\u00ec sao? \u2013 S\u1eeda b\u00e0i, c\u00e1c nh\u00f3m tr\u00ecnh b\u00e0y tr\u01b0\u1edbc l\u1edbp. GV gi\u00fap c\u00e1c em di\u1ec5n \u0111\u1ea1t, gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m. B\u00e0i 4: \u2013 HS nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i. \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb nh\u00f3m \u0111\u00f4i. \u2013 S\u1eeda b\u00e0i, HS tr\u00ecnh b\u00e0y v\u00e0 gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m. GV h\u1ec7 th\u1ed1ng ho\u00e1 c\u00e1ch so s\u00e1nh; t\u00ecm s\u1ed1 l\u1edbn nh\u1ea5t, s\u1ed1 b\u00e9 nh\u1ea5t v\u00e0 s\u1eafp x\u1ebfp s\u1ed1 t\u1ef1 nhi\u00ean. a) + \u0110\u1ea7u ti\u00ean d\u1ef1a v\u00e0o s\u1ed1 ch\u1eef s\u1ed1 c\u1ee7a c\u00e1c s\u1ed1: S\u1ed1 c\u00f3 nhi\u1ec1u ch\u1eef s\u1ed1 h\u01a1n th\u00ec l\u1edbn h\u01a1n v\u00e0 ng\u01b0\u1ee3c l\u1ea1i. \u2192 X\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c s\u1ed1 b\u00e9 nh\u1ea5t l\u00e0 351\u2009456 (s\u1ed1 c\u00f3 \u00edt ch\u1eef s\u1ed1 nh\u1ea5t). + Ti\u1ebfp theo so s\u00e1nh c\u00e1c s\u1ed1 c\u00f3 s\u1ed1 ch\u1eef s\u1ed1 b\u1eb1ng nhau. So s\u00e1nh t\u1eeb h\u00e0ng cao nh\u1ea5t: \u2192 1\u2009134\u2009310 b\u00e9 h\u01a1n hai s\u1ed1 c\u00f2n l\u1ea1i. 313","So s\u00e1nh \u1edf h\u00e0ng k\u1ebf ti\u1ebfp: \u2192 8\u2009053\u2009663 < 8\u2009993\u2009082 \u2192 8\u2009993\u2009082 l\u00e0 s\u1ed1 l\u1edbn nh\u1ea5t. V\u1eady s\u1ed1 l\u1edbn nh\u1ea5t l\u00e0 8\u2009993\u2009082, s\u1ed1 b\u00e9 nh\u1ea5t l\u00e0 351\u2009456. \u2192 Th\u00e0nh ph\u1ed1 H\u1ed3 Ch\u00ed Minh nhi\u1ec1u d\u00e2n nh\u1ea5t, th\u00e0nh ph\u1ed1 Hu\u1ebf \u00edt d\u00e2n nh\u1ea5t. b) S\u1ed1 d\u00e2n s\u1eafp x\u1ebfp theo th\u1ee9 t\u1ef1 t\u1eeb l\u1edbn \u0111\u1ebfn b\u00e9 l\u00e0: 8\u2009993\u2009082; 8\u2009053\u2009663; 1\u2009134\u2009310; 351\u2009456 \u2192 C\u00e1c th\u00e0nh ph\u1ed1 c\u00f3 s\u1ed1 d\u00e2n s\u1eafp x\u1ebfp theo th\u1ee9 t\u1ef1 t\u1eeb nhi\u1ec1u d\u00e2n \u0111\u1ebfn \u00edt d\u00e2n: Th\u00e0nh ph\u1ed1 H\u1ed3 Ch\u00ed Minh, th\u00e0nh ph\u1ed1 H\u00e0 N\u1ed9i, th\u00e0nh ph\u1ed1 \u0110\u00e0 n\u1eb5ng, th\u00e0nh ph\u1ed1 Hu\u1ebf. B\u00e0i 5: \u2013 C\u00f3 th\u1ec3 t\u1ed5 ch\u1ee9c \u0111\u1ec3 c\u00e1c nh\u00f3m GQV\u0110. \u2022 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: a) T\u00ecm s\u1ed1 c\u00e1c s\u1ed1 t\u1ef1 nhi\u00ean c\u00f3 m\u1ed9t ch\u1eef s\u1ed1. T\u00ecm s\u1ed1 c\u00e1c s\u1ed1 t\u1ef1 nhi\u00ean c\u00f3 hai ch\u1eef s\u1ed1. b) Vi\u1ebft s\u1ed1 l\u1edbn nh\u1ea5t c\u00f3 n\u0103m ch\u1eef s\u1ed1 (d\u00f9ng c\u1ea3 n\u0103m ch\u1eef s\u1ed1 2, 5, 3, 0, 7). Vi\u1ebft s\u1ed1 b\u00e9 nh\u1ea5t c\u00f3 n\u0103m ch\u1eef s\u1ed1 (d\u00f9ng c\u1ea3 n\u0103m ch\u1eef s\u1ed1 2, 5, 3, 0, 7). \u2022 B\u01b0\u1edbc 2: L\u1eadp k\u1ebf ho\u1ea1ch N\u00eau \u0111\u01b0\u1ee3c c\u00e1ch th\u1ee9c GQV\u0110. a) M\u1ed9t ch\u1eef s\u1ed1. D\u00e3y s\u1ed1 t\u1ef1 nhi\u00ean c\u00f3 m\u1ed9t ch\u1eef s\u1ed1 b\u1eaft \u0111\u1ea7u t\u1eeb s\u1ed1 n\u00e0o, k\u1ebft th\u00fac l\u00e0 s\u1ed1 n\u00e0o? (S\u1ed1 0 c\u00f3 l\u00e0 s\u1ed1 c\u00f3 m\u1ed9t ch\u1eef s\u1ed1?) \u2192 \u0110\u1ebfm. Hai ch\u1eef s\u1ed1. D\u00e3y s\u1ed1 t\u1ef1 nhi\u00ean c\u00f3 hai ch\u1eef s\u1ed1 b\u1eaft \u0111\u1ea7u t\u1eeb s\u1ed1 n\u00e0o, k\u1ebft th\u00fac l\u00e0 s\u1ed1 n\u00e0o? \u2192 \u0110\u1ebfm ho\u1eb7c t\u00ednh. b) \u0110\u1ec3 c\u00f3 s\u1ed1 l\u1edbn nh\u1ea5t ho\u1eb7c b\u00e9 nh\u1ea5t, ch\u1eef s\u1ed1 h\u00e0ng n\u00e0o s\u1ebd quy\u1ebft \u0111\u1ecbnh? (Khi so s\u00e1nh c\u00e1c s\u1ed1 t\u1ef1 nhi\u00ean c\u00f3 s\u1ed1 ch\u1eef s\u1ed1 b\u1eb1ng nhau, ta so s\u00e1nh t\u1eeb h\u00e0ng n\u00e0o \u0111\u1ebfn h\u00e0ng n\u00e0o?) 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 tr\u01b0\u1edbc l\u1edbp, GV gi\u00fap HS di\u1ec5n \u0111\u1ea1t, h\u1ec7 th\u1ed1ng ho\u00e1 c\u00e1ch l\u00e0m. a) C\u00e1c s\u1ed1 c\u00f3 m\u1ed9t ch\u1eef s\u1ed1: 0; 1; 2; 3; 4; 5; 6; 7; 8; 9 \u2192 C\u00f3 10 s\u1ed1. C\u00e1c s\u1ed1 c\u00f3 hai ch\u1eef s\u1ed1: 10; 11; 12; 13; \u2026; 98; 99. C\u00f3 th\u1ec3 c\u00f3 nhi\u1ec1u c\u00e1ch l\u00e0m: + \u0110\u1ebfm l\u1ea7n l\u01b0\u1ee3t c\u00e1c s\u1ed1 trong d\u00e3y s\u1ed1 \u2192 C\u00f3 90 s\u1ed1. 314","+ X\u1ebfp th\u00e0nh t\u1eebng ch\u1ee5c: 10; 11; 12; \u2026; 19; 20; 21; 22; \u2026; 29; 30; 31; 32; \u2026; 39; \u2026 90; 91; 92; \u2026; 99. \u2192 T\u00ednh: M\u1ed7i h\u00e0ng c\u00f3 10 s\u1ed1. C\u00f3 9 h\u00e0ng n\u00ean c\u00f3 90 s\u1ed1. + T\u00ednh: T\u1eeb 1 \u0111\u1ebfn 99 c\u00f3 99 s\u1ed1 c\u00f3 m\u1ed9t ch\u1eef s\u1ed1 v\u00e0 hai ch\u1eef s\u1ed1, trong \u0111\u00f3 c\u00f3 9 s\u1ed1 c\u00f3 m\u1ed9t ch\u1eef s\u1ed1 (t\u1eeb 1 \u0111\u1ebfn 9), \u2192 C\u00f3 90 s\u1ed1 c\u00f3 hai ch\u1eef s\u1ed1 (99 \u2013 9 = 90). b) C\u00e1c ch\u1eef s\u1ed1 s\u1ebd d\u00f9ng \u0111\u1ec3 vi\u1ebft: 2, 5, 3, 0, 7 (d\u00f9ng c\u1ea3 n\u0103m ch\u1eef s\u1ed1). Trong c\u00e1c s\u1ed1 c\u00f3 n\u0103m ch\u1eef s\u1ed1 tr\u00ean: + S\u1ed1 l\u1edbn nh\u1ea5t l\u00e0 s\u1ed1 \u0111\u01b0\u1ee3c vi\u1ebft b\u1edfi c\u00e1c ch\u1eef s\u1ed1 t\u1eeb l\u1edbn \u0111\u1ebfn b\u00e9 (t\u1eeb h\u00e0ng cao \u0111\u1ebfn h\u00e0ng th\u1ea5p) \u2192 75 320. + S\u1ed1 b\u00e9 nh\u1ea5t l\u00e0 s\u1ed1 \u0111\u01b0\u1ee3c vi\u1ebft b\u1edfi c\u00e1c ch\u1eef s\u1ed1 t\u1eeb b\u00e9 \u0111\u1ebfn l\u1edbn (t\u1eeb h\u00e0ng cao \u0111\u1ebfn h\u00e0ng th\u1ea5p). Tuy nhi\u00ean, ch\u1eef s\u1ed1 0 kh\u00f4ng th\u1ec3 \u0111\u1ee9ng \u0111\u1ea7u (khi \u0111\u00f3 s\u1ebd l\u00e0 s\u1ed1 c\u00f3 b\u1ed1n ch\u1eef s\u1ed1) \u2192 20 357. B\u01b0\u1edbc 4: Ki\u1ec3m tra l\u1ea1i a) Vi\u1ec7c \u0111\u1ebfm v\u00e0 t\u00ednh to\u00e1n c\u00f3 \u0111\u00fang kh\u00f4ng? b) C\u00f3 s\u1ed1 n\u00e0o l\u1edbn h\u01a1n ho\u1eb7c b\u00e9 h\u01a1n hai s\u1ed1 v\u1eeba vi\u1ebft kh\u00f4ng? B\u00e0i 6: \u2013 HS (nh\u00f3m b\u1ed1n) nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i. \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb nh\u00f3m b\u1ed1n. \u2013 S\u1eeda b\u00e0i, HS tr\u00ecnh b\u00e0y v\u00e0 gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m. \u2013 GV gi\u00fap c\u00e1c em kh\u00e1i qu\u00e1t ho\u00e1 c\u00e1c t\u00ednh ch\u1ea5t ph\u00e9p t\u00ednh. Ch\u1eb3ng h\u1ea1n: a) a + b = b + a (Khi ta \u0111\u1ed5i ch\u1ed7 c\u00e1c s\u1ed1 h\u1ea1ng c\u1ee7a m\u1ed9t t\u1ed5ng th\u00ec t\u1ed5ng kh\u00f4ng thay \u0111\u1ed5i.) \u2026 b) a \u2013 a \u2192 0 (M\u1ed9t s\u1ed1 tr\u1eeb \u0111i ch\u00ednh n\u00f3 th\u00ec b\u1eb1ng 0.) \u2026 B\u00e0i 7: \u2013 HS (nh\u00f3m \u0111\u00f4i) nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i, th\u1ea3o lu\u1eadn. + Th\u1ee9 t\u1ef1 th\u1ef1c hi\u1ec7n ph\u00e9p t\u00ednh. + \u00c1p d\u1ee5ng t\u00ednh ch\u1ea5t ph\u00e9p t\u00ednh. + Ch\u1ecdn c\u00e1ch thu\u1eadn ti\u1ec7n. + N\u1ebfu c\u00f3 th\u1ec3, n\u00ean t\u00ednh nh\u1ea9m. 315","\u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb nh\u00f3m b\u1ed1n. \u2013 S\u1eeda b\u00e0i, HS tr\u00ecnh b\u00e0y v\u00e0 gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m (ph\u1ea7n gi\u1ea3i th\u00edch ch\u1ec9 c\u1ea7n n\u00f3i, kh\u00f4ng c\u1ea7n vi\u1ebft). a) 47 000 + 8 000 + 3 000 = (47 000 + 3 000) + 8 000 (T\u00ednh ch\u1ea5t giao ho\u00e1n, t\u00ednh ch\u1ea5t k\u1ebft h\u1ee3p) = 50 000 + 8 000 (47 ngh\u00ecn + 3 ngh\u00ecn = 50 ngh\u00ecn) = 58 000 250 000 \u2013 5 \u00d7 10 000 = 250 000 \u2013 50 000 (5 \u00d7 1 ch\u1ee5c ngh\u00ecn = 5 ch\u1ee5c ngh\u00ecn) = 200 000 20 \u00d7 3 \u00d7 5 \u00d7 7 = (3 \u00d7 7) \u00d7 (20 \u00d7 5) (T\u00ednh ch\u1ea5t giao ho\u00e1n, t\u00ednh ch\u1ea5t k\u1ebft h\u1ee3p) = 21 \u00d7 100 = 2 100 (Th\u00eam 00 v\u00e0o b\u00ean ph\u1ea3i c\u1ee7a 21) b) \u2026 92 \u00d7 753 \u2013 82 \u00d7 753 = (92 \u2013 82) \u00d7 753 (Quy t\u1eafc m\u1ed9t hi\u1ec7u nh\u00e2n v\u1edbi m\u1ed9t s\u1ed1) = 10 \u00d7 753 = 7 530 (Th\u00eam 0 v\u00e0o b\u00ean ph\u1ea3i c\u1ee7a 753) B\u00e0i 8: \u2013 HS nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i: \u0110\u1eb7t t\u00ednh r\u1ed3i t\u00ednh. L\u01b0u \u00fd tr\u01b0\u1edbc khi l\u00e0m. + Ph\u00e9p c\u1ed9ng, ph\u00e9p tr\u1eeb: \u0110\u1eb7t t\u00ednh c\u1ea9n th\u1eadn; l\u01b0u \u00fd c\u00f3 nh\u1edb. + Ph\u00e9p nh\u00e2n: T\u00edch ri\u00eang th\u1ee9 hai vi\u1ebft t\u1eeb h\u00e0ng ch\u1ee5c; l\u01b0u \u00fd c\u00f3 nh\u1edb. + Ph\u00e9p chia: \u0110\u1eb7t t\u00ednh \u2192 Chia (B\u1eaft ch\u1eef s\u1ed1 \u2013 Nh\u1ea9m th\u01b0\u01a1ng \u2013 Th\u1eed) \u2192 Nh\u00e2n \u2192 Tr\u1eeb \u2192 H\u1ea1. \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb nh\u00f3m \u0111\u00f4i. \u2013 S\u1eeda b\u00e0i, HS tr\u00ecnh b\u00e0y c\u00e1ch l\u00e0m. B\u00e0i 9: \u2013 HS (nh\u00f3m \u0111\u00f4i) nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i, th\u1ea3o lu\u1eadn. + Th\u1ee9 t\u1ef1 th\u1ef1c hi\u1ec7n ph\u00e9p t\u00ednh. + Nh\u1eefng l\u01b0u \u00fd khi t\u00ednh. \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb nh\u00f3m b\u1ed1n. \u2013 S\u1eeda b\u00e0i, HS tr\u00ecnh b\u00e0y c\u00e1ch l\u00e0m. B\u00e0i 10: \u2013 HS (nh\u00f3m \u0111\u00f4i) nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i, th\u1ea3o lu\u1eadn. T\u00ecm th\u00e0nh ph\u1ea7n ch\u01b0a bi\u1ebft trong ph\u00e9p t\u00ednh. \u2192 C\u00e1c quy t\u1eafc c\u1ea7n nh\u1eafc l\u1ea1i? 316","\u2192 N\u1ebfu qu\u00ean? (Vi\u1ebft m\u1ed9t ph\u00e9p t\u00ednh \u0111\u01a1n gi\u1ea3n t\u01b0\u01a1ng t\u1ef1 ph\u00e9p t\u00ednh \u0111ang l\u00e0m.) C\u00e2u c) n\u00ean d\u00f9ng tr\u01b0\u1eddng h\u1ee3p tr\u1eeb \u0111\u1eb7c bi\u1ec7t. \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb nh\u00f3m \u0111\u00f4i. \u2013 S\u1eeda b\u00e0i, HS tr\u00ecnh b\u00e0y c\u00e1ch l\u00e0m. III. V\u1eadn d\u1ee5ng, tr\u1ea3i nghi\u1ec7m B\u00e0i 11: \u2013 HS (nh\u00f3m \u0111\u00f4i) \u0111\u1ecdc k\u0129 b\u00e0i, nh\u1eadn bi\u1ebft c\u00e1i \u0111\u00e3 cho v\u00e0 c\u00e1i ph\u1ea3i t\u00ecm. \u2013 Quan s\u00e1t tranh, nh\u1eadn bi\u1ebft Toa \u2013 D\u00e3y \u2013 H\u00e0ng \u2013 Gh\u1ebf. N\u00f3i ng\u1eafn g\u1ecdn l\u1ea1i b\u00e0i to\u00e1n. Ch\u1eb3ng h\u1ea1n: M\u1ed7i toa: 2 d\u00e3y M\u1ed7i d\u00e3y: 16 h\u00e0ng M\u1ed7i h\u00e0ng: 2 ch\u1ed7 C\u1ea7n bao nhi\u00eau toa \u0111\u1ec3 ch\u1edf h\u1ebft 175 h\u1ecdc sinh? \u2013 Th\u1ea3o lu\u1eadn. + Mu\u1ed1n bi\u1ebft c\u00f3 bao nhi\u00eau toa ch\u1edf h\u1ebft 175 h\u1ecdc sinh c\u1ea7n bi\u1ebft m\u1ed7i toa ch\u1edf bao nhi\u00eau h\u1ecdc sinh. + M\u1ed7i d\u00e3y: 16 h\u00e0ng M\u1ed7i h\u00e0ng: 2 ch\u1ed7 (t\u1ee9c l\u00e0 2 HS) \u2192 T\u00ecm \u0111\u01b0\u1ee3c s\u1ed1 HS m\u1ed7i d\u00e3y. M\u1ed9t toa c\u00f3 2 d\u00e3y \u2192 T\u00ecm \u0111\u01b0\u1ee3c s\u1ed1 HS m\u1ed7i toa. Bi\u1ebft s\u1ed1 h\u1ecdc sinh c\u1ea7n ch\u1edf: 175 \u2192 T\u00ecm s\u1ed1 toa. \u2013 HS l\u00e0m b\u00e0i c\u00e1 nh\u00e2n, chia s\u1ebb nh\u00f3m b\u1ed1n. B\u00e0i gi\u1ea3i 2 \u00d7 16 = 32 M\u1ed7i d\u00e3y c\u00f3 32 h\u1ecdc sinh. 32 \u00d7 2 = 64 M\u1ed7i toa ch\u1edf 64 h\u1ecdc sinh. 175 : 64 = 2 (d\u01b0 47) C\u1ea7n 2 toa ch\u1edf \u0111\u1ea7y h\u1ecdc sinh, 47 h\u1ecdc sinh d\u01b0 s\u1ebd ng\u1ed3i v\u00e0o toa th\u1ee9 ba. V\u1eady c\u1ea7n \u00edt nh\u1ea5t 3 toa t\u00e0u \u0111\u1ec3 ch\u1edf h\u1ebft 175 h\u1ecdc sinh. \u2013 S\u1eeda b\u00e0i, GV gi\u00fap HS gi\u1ea3i th\u00edch t\u1ea1i sao ch\u1ecdn ph\u00e9p t\u00ednh \u0111\u00f3. Ch\u1eb3ng h\u1ea1n: + M\u1ed7i h\u00e0ng gh\u1ebf c\u00f3 2 h\u1ecdc sinh. C\u00f3 16 h\u00e0ng gh\u1ebf \u2192 2 \u0111\u01b0\u1ee3c l\u1ea5y 16 l\u1ea7n \u2192 2 \u00d7 16 = 32 317","+ M\u1ed7i d\u00e3y c\u00f3 32 h\u1ecdc sinh. C\u00f3 2 d\u00e3y \u2192 32 \u0111\u01b0\u1ee3c l\u1ea5y 2 l\u1ea7n \u2192 32 \u00d7 2 = 64 + X\u1ebfp 175 h\u1ecdc sinh v\u00e0o c\u00e1c toa, m\u1ed7i toa 64 h\u1ecdc sinh \u2192 175 : 64 = 2 (toa) (d\u01b0 47 h\u1ecdc sinh) C\u0169ng c\u00f3 th\u1ec3 t\u00ednh theo c\u00e1ch kh\u00e1c: T\u00ednh s\u1ed1 h\u00e0ng gh\u1ebf m\u1ed7i toa \u2192 T\u00ednh s\u1ed1 HS m\u1ed7i toa \u2192 T\u00ednh s\u1ed1 toa. Th\u1eed th\u00e1ch \u2013 HS (nh\u00f3m \u0111\u00f4i) nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i, th\u1ea3o lu\u1eadn. \u0110\u1ebfm xem c\u00f3 bao nhi\u00eau ti\u1ec1n. \u2192 D\u00f9ng s\u1ed1 ti\u1ec1n tr\u00ean \u0111\u1ec3 mua 1 xe \u0111\u1ea1p v\u00e0 1 m\u0169 b\u1ea3o hi\u1ec3m. \u2192 Xe n\u00e0o, m\u0169 b\u1ea3o hi\u1ec3m n\u00e0o? \u2013 HS th\u1ef1c hi\u1ec7n (nh\u00f3m \u0111\u00f4i) r\u1ed3i chia s\u1ebb nh\u00f3m b\u1ed1n. + \u0110\u1ebfm ti\u1ec1n theo m\u1ec7nh gi\u00e1 c\u00e1c t\u1edd ti\u1ec1n t\u1eeb cao \u0111\u1ebfn th\u1ea5p. 5 tr\u0103m \u2192 7 tr\u0103m \u2192 8 tr\u0103m \u2192 8 tr\u0103m 5 ch\u1ee5c \u2192 9 tr\u0103m \u2192 9 tr\u0103m 5 ch\u1ee5c \u2192 9 tr\u0103m 7 ch\u1ee5c \u2192 9 tr\u0103m 8 ch\u1ee5c \u2192 9 tr\u0103m 9 ch\u1ee5c \u2192 1 tri\u1ec7u C\u00f3 1 000 000 \u0111\u1ed3ng. + S\u1ed1 ti\u1ec1n xe v\u00e0 ti\u1ec1n m\u0169 b\u1ea3o hi\u1ec3m ph\u1ea3i b\u00e9 h\u01a1n 1 000 000 \u0111\u1ed3ng. C\u00f3 c\u00e1c c\u00e1ch l\u1ef1a ch\u1ecdn (n\u00ean nh\u1ea9m t\u00ednh v\u00ec kh\u00f4ng c\u00f3 s\u1eb5n gi\u1ea5y, b\u00fat): \u2022 N\u1ebfu mua xe 849 000 \u0111\u1ed3ng \u2192 G\u1ea7n 850 000 \u0111\u1ed3ng \t \u2192 C\u00f2n kho\u1ea3ng 150 000 \u0111\u1ed3ng \u0111\u1ec3 mua m\u0169 b\u1ea3o hi\u1ec3m \t \u2192 Ch\u1ecdn m\u0169 b\u1ea3o hi\u1ec3m 129 000 \u0111\u1ed3ng. \u2022 N\u1ebfu mua xe 912 000 \u0111\u1ed3ng \u2192 C\u00f2n ch\u01b0a t\u1edbi 100 000 \u0111\u1ed3ng \t \u2192 Kh\u00f4ng \u0111\u1ee7 ti\u1ec1n mua m\u0169 b\u1ea3o hi\u1ec3m. \t (Gi\u00e1 m\u1ed7i c\u00e1i m\u0169 b\u1ea3o hi\u1ec3m \u0111\u1ec1u l\u1edbn h\u01a1n 100 000 \u0111\u1ed3ng.) \u2022 N\u1ebfu mua xe 749 000 \u0111\u1ed3ng \u2192 G\u1ea7n 750 000 \u0111\u1ed3ng \t \u2192 C\u00f2n kho\u1ea3ng 250 000 \u0111\u1ed3ng \u0111\u1ec3 mua m\u0169 b\u1ea3o hi\u1ec3m \t \u2192 Ch\u1ecdn m\u0169 b\u1ea3o hi\u1ec3m 129 000 \u0111\u1ed3ng ho\u1eb7c 217 000 \u0111\u1ed3ng. \u2013 S\u1eeda b\u00e0i, c\u00e1c nh\u00f3m tr\u00ecnh b\u00e0y v\u00e0 gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m. Kh\u00e1m ph\u00e1 \u2013 HS (nh\u00f3m b\u1ed1n) \u0111\u1ecdc k\u0129 \u0111o\u1ea1n v\u0103n, t\u00ecm hi\u1ec3u th\u00f4ng tin v\u00e0 l\u00e0m b\u00e0i. \u2013 S\u1eeda b\u00e0i, GV h\u01b0\u1edbng d\u1eabn HS h\u00ecnh dung \u0111\u1ed9 l\u1edbn c\u1ee7a c\u00e1c s\u1ed1 \u0111o. + 330 cm = 300 cm + 30 cm = 3 m 30 cm 318","\u2192 D\u00e0i b\u1eb1ng m\u1ea5y c\u00e1i b\u00e0n HS? + 2 t\u1ea5n \u2192 N\u1ebfu trung b\u00ecnh m\u1ed7i HS n\u1eb7ng 30 kg th\u00ec bao nhi\u00eau em m\u1edbi n\u1eb7ng b\u1eb1ng con c\u00e1? 2 t\u1ea5n = 2 \u00d7 1 000 kg = 2 000 kg 2 000 : 30 = 66 (d\u01b0 20) \u2192 Kho\u1ea3ng 67 em s\u1ebd n\u1eb7ng b\u1eb1ng con c\u00e1. + S\u1ed1 tr\u00f2n tr\u0103m tri\u1ec7u b\u00e9 nh\u1ea5t l\u00e0 s\u1ed1 n\u00e0o? (100 000 000) + G\u1ea5p 3 l\u1ea7n s\u1ed1 tr\u00f2n tr\u0103m tri\u1ec7u b\u00e9 nh\u1ea5t ta \u0111\u01b0\u1ee3c s\u1ed1 n\u00e0o? (100 000 000 \u00d7 3 = 300 000 000) \u2192 C\u00e1 c\u00e1i m\u1ed7i l\u1ea7n \u0111\u1ebb kho\u1ea3ng 300 000 000 tr\u1ee9ng. \u00d4N T\u1eacP PH\u00c2N S\u1ed0 V\u00c0 C\u00c1C PH\u00c9P T\u00cdNH (3 ti\u1ebft) I. Kh\u1edfi \u0111\u1ed9ng C\u00f3 th\u1ec3 d\u00f9ng m\u1ed9t tr\u00f2 ch\u01a1i chuy\u1ec3n t\u1ea3i c\u00e1c n\u1ed9i dung (ng\u1eafn g\u1ecdn): \u2013 Ph\u00e2n s\u1ed1 c\u00f3 ph\u1ea3i l\u00e0 m\u1ed9t s\u1ed1 kh\u00f4ng? M\u1eabu s\u1ed1 bi\u1ec3u th\u1ecb g\u00ec, t\u1eed s\u1ed1 bi\u1ec3u th\u1ecb g\u00ec? Cho v\u00ed d\u1ee5. \u2013 So s\u00e1nh ph\u00e2n s\u1ed1, ph\u00e2n s\u1ed1 b\u00e9 nh\u1ea5t, ph\u00e2n s\u1ed1 l\u1edbn nh\u1ea5t. \u2013 C\u00e1c ph\u00e9p t\u00ednh v\u1edbi ph\u00e2n s\u1ed1. \u2026 II. Th\u1ef1c h\u00e0nh, luy\u1ec7n t\u1eadp B\u00e0i 1: \u2013 HS (nh\u00f3m \u0111\u00f4i) nh\u1eadn bi\u1ebft 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, HS tr\u00ecnh b\u00e0y v\u00e0 gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m a) B (7 ph\u1ea7n ph\u1ea3i b\u1eb1ng nhau) 12 6 b) B (r\u00fat g\u1ecdn 16 \u0111\u01b0\u1ee3c 8 ) B\u00e0i 2: \u2013 HS (nh\u00f3m \u0111\u00f4i) nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i. Vi\u1ebft c\u00e1c ph\u00e2n s\u1ed1 \u0111\u01b0\u1ee3c so s\u00e1nh v\u1edbi 1. \u2192 Nh\u1eafc l\u1ea1i: + N\u1ebfu t\u1eed s\u1ed1 b\u00e9 h\u01a1n m\u1eabu s\u1ed1 th\u00ec ph\u00e2n s\u1ed1 b\u00e9 h\u01a1n 1. + N\u1ebfu t\u1eed s\u1ed1 b\u1eb1ng m\u1eabu s\u1ed1 th\u00ec ph\u00e2n s\u1ed1 b\u1eb1ng 1. + N\u1ebfu t\u1eed s\u1ed1 l\u1edbn h\u01a1n m\u1eabu s\u1ed1 th\u00ec ph\u00e2n s\u1ed1 l\u1edbn h\u01a1n 1. (M\u1eabu s\u1ed1 c\u1ee7a c\u00e1c ph\u00e2n s\u1ed1 lu\u00f4n kh\u00e1c 0.) \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. 3 3 V\u00ed d\u1ee5: 4 < 1 v\u00ec 4 c\u00f3 t\u1eed s\u1ed1 b\u00e9 h\u01a1n m\u1eabu s\u1ed1 \u2026 319","B\u00e0i 3: \u2013 HS (nh\u00f3m \u0111\u00f4i) nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i. \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb nh\u00f3m b\u1ed1n. \u2013 S\u1eeda b\u00e0i, HS tr\u00ecnh b\u00e0y v\u00e0 gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m. GV h\u1ec7 th\u1ed1ng ho\u00e1 c\u00e1ch l\u00e0m c\u1ee7a c\u00e1c nh\u00f3m. 6 ) \u2192 So s\u00e1nh \u2192 S\u1eafp x\u1ebfp. + Th\u00f4ng th\u01b0\u1eddng ta quy \u0111\u1ed3ng m\u1eabu s\u1ed1 c\u00e1c ph\u00e2n s\u1ed1 (1 = 6 + Tuy nhi\u00ean, \u1edf \u0111\u00e2y c\u00f3 1 n\u00ean ngh\u0129 t\u1edbi c\u00e1ch so s\u00e1nh ph\u00e2n s\u1ed1 v\u1edbi 1: 2 c\u00f3 t\u1eed s\u1ed1 b\u00e9 h\u01a1n m\u1eabu s\u1ed1 \u2192 2 <1 3 3 7 v\u00e0 3 c\u00f3 t\u1eed s\u1ed1 l\u1edbn h\u01a1n m\u1eabu s\u1ed1 \u2192 7 ; 3 >1 6 2 6 2 \u2192 So s\u00e1nh 7 v\u00e0 3 6 2 \u2192 Quy \u0111\u1ed3ng m\u1eabu s\u1ed1 \u0111\u01b0\u1ee3c 7 v\u00e0 9 6 6 \u2192 7 < 3 6 2 Ta s\u1eafp x\u1ebfp nh\u01b0 sau: 2 ; 1; 7 ; 3 . 3 6 2 B\u00e0i 4: \u2013 HS nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i. T\u00ednh (c\u1ed9ng, tr\u1eeb, nh\u00e2n, chia v\u1edbi ph\u00e2n s\u1ed1). \u2192 Nh\u1eafc l\u1ea1i c\u00e1ch t\u00ednh v\u1edbi ph\u00e2n s\u1ed1: + C\u1ed9ng, tr\u1eeb: Quy \u0111\u1ed3ng m\u1eabu s\u1ed1 \u2192 C\u1ed9ng, tr\u1eeb t\u1eed; gi\u1eef nguy\u00ean m\u1eabu s\u1ed1. + Nh\u00e2n: T\u1eed nh\u00e2n t\u1eed, m\u1eabu nh\u00e2n m\u1eabu \u2192 R\u00fat g\u1ecdn \u2192 K\u1ebft qu\u1ea3. + Chia: Ph\u00e2n s\u1ed1 th\u1ee9 nh\u1ea5t gi\u1eef nguy\u00ean nh\u00e2n v\u1edbi ph\u00e2n s\u1ed1 th\u1ee9 hai \u0111\u1ea3o ng\u01b0\u1ee3c. C\u00e1c tr\u01b0\u1eddng h\u1ee3p \u0111\u1eb7c bi\u1ec7t n\u00ean l\u00e0m ng\u1eafn g\u1ecdn. \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb nh\u00f3m \u0111\u00f4i. \u2013 S\u1eeda b\u00e0i, HS tr\u00ecnh b\u00e0y v\u00e0 gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m. L\u01b0u \u00fd: 1 2 1 8 8 4 \u00d72 = 1\u00d7 = 18 : 1 = 18 (S\u1ed1 n\u00e0o chia cho 1 c\u0169ng b\u1eb1ng ch\u00ednh s\u1ed1 \u0111\u00f3.) 27 27 B\u00e0i 5: \u2013 HS (nh\u00f3m b\u1ed1n) nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i. \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb nh\u00f3m b\u1ed1n. \u2013 S\u1eeda b\u00e0i, HS tr\u00ecnh b\u00e0y v\u00e0 gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m. 320","GV h\u1ec7 th\u1ed1ng ho\u00e1 c\u00e1ch l\u00e0m. 3 a) 8 \u2013 .?. = 0 Thay .?. b\u1eb1ng 3 v\u00ec hai s\u1ed1 c\u00f3 hi\u1ec7u b\u1eb1ng 0 th\u00ec hai s\u1ed1 \u0111\u00f3 b\u1eb1ng nhau. 8 2 b) .?. \u00d7 9 =2 N\u1ebfu qu\u00ean quy t\u1eafc t\u00ecm th\u1eeba s\u1ed1: \u2192 Vi\u1ebft ph\u00e9p t\u00ednh \u0111\u01a1n gi\u1ea3n, ch\u1eb3ng h\u1ea1n 3 \u00d7 4 = 12 \u2192 L\u1ea5y tay che: \t 3 \u00d7 4 = 12 \u2192 T\u00ecm s\u1ed1 b\u1ecb che: \t12 : 42 \u2192 T\u01b0\u01a1ng t\u1ef1 v\u1edbi b\u00e0i: 9 \t .?. \u00d7 =2 \u2192 \t 2: 2 9 15 \t\u2026 17 c) .?. : =0 Thay .?. b\u1eb1ng 0 v\u00ec 0 chia cho b\u1ea5t k\u00ec s\u1ed1 n\u00e0o (kh\u00e1c 0) c\u0169ng b\u1eb1ng 0. B\u00e0i 6: \u2013 HS nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i: T\u00ednh (gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ec3u th\u1ee9c). \u2192 Nh\u1eafc l\u1ea1i: + Th\u1ee9 t\u1ef1 th\u1ef1c hi\u1ec7n c\u00e1c ph\u00e9p t\u00ednh. + \u00c1p d\u1ee5ng c\u00e1c t\u00ednh ch\u1ea5t ph\u00e9p t\u00ednh. + Ch\u1ecdn c\u00e1ch l\u00e0m thu\u1eadn ti\u1ec7n. \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. GV h\u1ec7 th\u1ed1ng ho\u00e1 c\u00e1ch l\u00e0m. 3 2 17 6 2 17 a) \uf8eb 4 + 8 \uf8f6 \u00d7 18 = \uf8eb 8 + 8 \uf8f6 \u00d7 18 \uf8ed\uf8ec \uf8f8\uf8f7 \uf8ec\uf8ed \uf8f8\uf8f7 = 1 \u00d7 17 18 = 17 18 b) 3 \u00d7 5 \u2212 1 \u00d7 5 = \uf8eb 3 \u2212 1 \uf8f6 \u00d7 5 (m\u1ed9t hi\u1ec7u nh\u00e2n m\u1ed9t s\u1ed1) 2 8 2 8 \uf8ec\uf8ed 2 2 \uf8f7\uf8f8 8 \t\t =1\u00d7 5 8 5 = 8 321","III. V\u1eadn d\u1ee5ng, tr\u1ea3i nghi\u1ec7m B\u00e0i 7: \u2013 HS nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i. Nh\u1eadn d\u1ea1ng \u0111\u01b0\u1ee3c b\u00e0i to\u00e1n \u201ct\u1ed5ng \u2013 hi\u1ec7u\u201d. \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n. \u2013 S\u1eeda b\u00e0i, HS tr\u00ecnh b\u00e0y v\u00e0 gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m. B\u00e0i 8: \u2013 HS nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i: X\u00e1c \u0111\u1ecbnh c\u00e2u \u0111\u00fang, c\u00e2u sai. \u2013 Ho\u1ea1t \u0111\u1ed9ng nh\u00f3m. Quan s\u00e1t th\u1eadt k\u0129 b\u1ee9c tranh, nh\u1eadn bi\u1ebft: + T\u1ea5t c\u1ea3 HS l\u1edbp 4D. + C\u00e1c b\u1ea1n tr\u1ed3ng c\u00e2y. + C\u00e1c b\u1ea1n v\u1ec7 sinh m\u00f4i tr\u01b0\u1eddng. + C\u00e1c b\u1ea1n ch\u0103m s\u00f3c ng\u01b0\u1eddi gi\u00e0. 1 . \u2013 GV gi\u1ea3i t\u00edch t\u1eeb \u201cm\u1ed9t n\u1eeda\u201d t\u1ee9c l\u00e0 2 \u2013 C\u00e1c nh\u00f3m th\u1ef1c hi\u1ec7n v\u00e0 tr\u00ecnh b\u00e0y, gi\u1ea3i th\u00edch. a) \u0110 ( 1 s\u1ed1 HS l\u1edbp 4D \u2192 1 \u00d7 32 = 8 \u2192 Trong tranh c\u00f3 9 b\u1ea1n.) b) S 4 4 c) S ( 1 s\u1ed1 HS l\u1edbp 4D \u2192 1 \u00d7 32 = 16 \u2192 Trong tranh c\u00f3 17 b\u1ea1n.) 2 2 d) \u0110 (9 : 6 = 9 = 3 ) 6 2 Th\u1eed th\u00e1ch \u2013 Ho\u1ea1t \u0111\u1ed9ng nh\u00f3m. \u2013 C\u00e1c nh\u00f3m th\u1ea3o lu\u1eadn, th\u1ef1c hi\u1ec7n r\u1ed3i tr\u00ecnh b\u00e0y tr\u01b0\u1edbc l\u1edbp. \u2013 S\u1eeda b\u00e0i, GV c\u00f3 th\u1ec3 d\u00f9ng h\u00ecnh \u1ea3nh \u0111\u1ec3 gi\u1ea3i th\u00edch. U\u1ed1ng R\u00f3t U\u1ed1ng R\u00f3t U\u1ed1ng th\u00eam th\u00eam Hai l\u1ea7n r\u00f3t th\u00eam n\u01b0\u1edbc l\u1ea7n l\u01b0\u1ee3t l\u00e0 1 c\u1ed1c v\u00e0 2 c\u1ed1c. 3 3 1 2 L\u01b0\u1ee3ng n\u01b0\u1edbc b\u1ea1n T\u00ed \u0111\u00e3 pha th\u00eam v\u00e0o c\u1ed1c n\u01b0\u1edbc chanh l\u00e0 1 c\u1ed1c. ( 3 + 3 = 1) 322","Ho\u1ea1t \u0111\u1ed9ng th\u1ef1c t\u1ebf \u2013 HS nh\u1eadn bi\u1ebft: S\u1ed1 h\u1ecdc sinh \u2026 trong l\u1edbp em \u2192 S\u1ed1 HS \u0111\u00f3 so v\u1edbi l\u1edbp em. Cho v\u00ed d\u1ee5. S\u1ed1 HS n\u1eef \/ S\u1ed1 HS c\u1ea3 l\u1edbp. Ch\u1eb3ng h\u1ea1n: \u2013 HS vi\u1ebft c\u00e1c ph\u00e2n s\u1ed1 theo y\u00eau c\u1ea7u ph\u00f9 h\u1ee3p v\u1edbi th\u1ef1c t\u1ebf l\u1edbp h\u1ecdc. \u00d4N T\u1eacP H\u00ccNH H\u1eccC V\u00c0 \u0110O L\u01af\u1edcNG (3 ti\u1ebft) I. Kh\u1edfi \u0111\u1ed9ng C\u00f3 th\u1ec3 d\u00f9ng m\u1ed9t tr\u00f2 ch\u01a1i ch\u1ecdn h\u00ecnh trong b\u1ed9 \u0111\u1ed3 d\u00f9ng h\u1ecdc to\u00e1n r\u1ed3i n\u00f3i \u0111\u1eb7c \u0111i\u1ec3m c\u1ee7a h\u00ecnh theo y\u00eau c\u1ea7u: \u2013 H\u00ecnh ph\u1eb3ng: h\u00ecnh thoi, h\u00ecnh b\u00ecnh h\u00e0nh, h\u00ecnh vu\u00f4ng, \u2026 \u2013 H\u00ecnh kh\u1ed1i: kh\u1ed1i tr\u1ee5, kh\u1ed1i l\u1eadp ph\u01b0\u01a1ng, \u2026 \u2026 II. Th\u1ef1c h\u00e0nh, luy\u1ec7n t\u1eadp B\u00e0i 1: \u2013 HS (nh\u00f3m \u0111\u00f4i) nh\u1eadn bi\u1ebft 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 nhau. \u2013 S\u1eeda b\u00e0i, HS n\u00f3i tr\u01b0\u1edbc l\u1edbp. H\u00ecnh b\u00ecnh h\u00e0nh, h\u00ecnh ch\u1eef nh\u1eadt, h\u00ecnh thoi, h\u00ecnh vu\u00f4ng. Trong c\u00e1c h\u00ecnh tr\u00ean: + H\u00ecnh c\u00f3 hai c\u1eb7p c\u1ea1nh \u0111\u1ed1i di\u1ec7n song song v\u1edbi nhau: C\u1ea3 b\u1ed1n h\u00ecnh tr\u00ean. + H\u00ecnh c\u00f3 b\u1ed1n c\u1ea1nh d\u00e0i b\u1eb1ng nhau: H\u00ecnh thoi, H\u00ecnh vu\u00f4ng. B\u00e0i 2: \u2013 HS (nh\u00f3m \u0111\u00f4i) nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i: G\u00f3c vu\u00f4ng, g\u00f3c nh\u1ecdn hay g\u00f3c t\u00f9? \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb nh\u00f3m b\u1ed1n. \u2013 S\u1eeda b\u00e0i, HS n\u00f3i tr\u01b0\u1edbc l\u1edbp. Trong t\u1ee9 gi\u00e1c ABCD: + G\u00f3c \u0111\u1ec9nh A, c\u1ea1nh AD, AB l\u00e0 g\u00f3c t\u00f9. (\u0110\u1eb7t \u00ea-ke v\u00e0o h\u00ecnh \u0111\u1ec3 minh ho\u1ea1.) + G\u00f3c \u0111\u1ec9nh B, c\u1ea1nh BA, BC l\u00e0 g\u00f3c vu\u00f4ng. (\u0110\u1eb7t \u00ea-ke v\u00e0o h\u00ecnh \u0111\u1ec3 minh ho\u1ea1.) + G\u00f3c \u0111\u1ec9nh C, c\u1ea1nh CB, CD l\u00e0 g\u00f3c t\u00f9. (\u0110\u1eb7t \u00ea-ke v\u00e0o h\u00ecnh \u0111\u1ec3 minh ho\u1ea1.) + G\u00f3c \u0111\u1ec9nh D, c\u1ea1nh DC, DA l\u00e0 g\u00f3c nh\u1ecdn. (\u0110\u1eb7t \u00ea-ke v\u00e0o h\u00ecnh \u0111\u1ec3 minh ho\u1ea1.) B\u00e0i 3: Ho\u1ea1t \u0111\u1ed9ng nh\u00f3m. \u2013 C\u00e1c nh\u00f3m nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i. \u2013 Th\u1ea3o lu\u1eadn. C\u00f3 th\u1ec3 d\u00f9ng \u0110DHT \u0111\u1ec3 th\u1ef1c hi\u1ec7n. \u2013 S\u1eeda b\u00e0i, c\u00e1c nh\u00f3m tr\u00ecnh b\u00e0y tr\u01b0\u1edbc l\u1edbp. 323","GV d\u00f9ng \u0110DDH minh ho\u1ea1. C\u00e1c h\u00ecnh khi gh\u00e9p l\u1ea1i \u0111\u01b0\u1ee3c kh\u1ed1i l\u1eadp ph\u01b0\u01a1ng: + H\u00ecnh A v\u00e0 H\u00ecnh M. + H\u00ecnh B v\u00e0 H\u00ecnh L. + H\u00ecnh C v\u00e0 H\u00ecnh N. Vui h\u1ecdc \u2013 HS (nh\u00f3m b\u1ed1n) nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u, quan s\u00e1t tranh. \u2013 Th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n r\u1ed3i chia s\u1ebb trong nh\u00f3m b\u1ed1n. \u2013 S\u1eeda b\u00e0i, c\u00e1c nh\u00f3m tr\u00ecnh b\u00e0y (ch\u1ec9 v\u00e0o h\u00ecnh \u0111\u1ec3 minh ho\u1ea1). a) Hai chi\u1ebfc xe ch\u1ea1y tr\u00ean hai con \u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c v\u1edbi nhau: + Xe m\u00e0u \u0111\u1ecf v\u00e0 xe m\u00e0u xanh d\u01b0\u01a1ng. + Xe m\u00e0u xanh l\u00e1 v\u00e0 xe m\u00e0u xanh d\u01b0\u01a1ng. b) Hai chi\u1ebfc xe ch\u1ea1y tr\u00ean hai con \u0111\u01b0\u1eddng song song v\u1edbi nhau: Xe m\u00e0u \u0111\u1ecf v\u00e0 xe m\u00e0u l\u00e1 c\u00e2y. Ho\u1ea1t \u0111\u1ed9ng th\u1ef1c t\u1ebf \u2013 HS (nh\u00f3m \u0111\u00f4i) \u0111\u1ecdc v\u0103n b\u1ea3n, nh\u1eadn bi\u1ebft c\u00e1c th\u00f4ng tin. + \u0110\u1eb7t thanh ngang vu\u00f4ng g\u00f3c v\u1edbi hai thanh d\u1ecdc. \u2013 Quan s\u00e1t h\u00ecnh \u1ea3nh, li\u00ean h\u1ec7 v\u1edbi c\u00e1c th\u00f4ng tin tr\u00ean. + D\u00f9ng \u00ea-ke \u0111\u1ec3 ki\u1ec3m tra g\u00f3c vu\u00f4ng. Th\u1eed th\u00e1ch \u2013 Ho\u1ea1t \u0111\u1ed9ng nh\u00f3m. \u2013 C\u00e1c nh\u00f3m nh\u1eadn bi\u1ebft c\u00e1c th\u00f4ng tin c\u1ea7n thi\u1ebft v\u00e0 c\u00e2u h\u1ecfi c\u1ee7a b\u00e0i. Th\u1ea3o lu\u1eadn \u0111\u1ec3 GQV\u0110. D\u00f9ng c\u00e1c que t\u00ednh d\u00e0i b\u1eb1ng nhau. \u2192 X\u1ebfp c\u00e1c h\u00ecnh thoi \u2192 M\u1ed7i que t\u00ednh l\u00e0 m\u1ed9t c\u1ea1nh c\u1ee7a m\u1ed9t h\u00ecnh thoi \u2192 Kh\u00f4ng c\u00f3 que t\u00ednh n\u00e0o l\u00e0 c\u1ea1nh chung c\u1ee7a hai h\u00ecnh thoi \u2192 4 que t\u00ednh x\u1ebfp \u0111\u01b0\u1ee3c 1 h\u00ecnh thoi \u2192 S\u1ed1 que t\u00ednh v\u1eeba \u0111\u1ee7 \u0111\u1ec3 x\u1ebfp c\u00e1c h\u00ecnh thoi ph\u1ea3i l\u00e0 s\u1ed1 chia h\u1ebft cho 4 \u2192 Th\u1eed: 281 : 4 (d\u01b0 1) \u2192 282 : 4 (d\u01b0 2); 283 : 4 (d\u01b0 3); 284 : 4 = 71 \u2192 Ch\u1ecdn D. (284) \u2013 S\u1eeda b\u00e0i, c\u00e1c nh\u00f3m tr\u00ecnh b\u00e0y tr\u01b0\u1edbc l\u1edbp. GV gi\u00fap c\u00e1c em di\u1ec5n \u0111\u1ea1t, gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m. B\u00e0i 4: \u2013 HS (nh\u00f3m \u0111\u00f4i) nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i: S\u1ed1? HS t\u00ecm c\u00e1ch th\u1ef1c hi\u1ec7n. a) S\u1ed1 \u1edf m\u1ed7i c\u1ed9t ch\u1ec9 m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c \u0111\u01a1n v\u1ecb \u0111o \u0111\u1ed9 d\u00e0i. 324","b) S\u1ed1 \u1edf m\u1ed7i c\u1ed9t ch\u1ec9 m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c \u0111\u01a1n v\u1ecb \u0111o di\u1ec7n t\u00edch \u2192 Nh\u1eafc l\u1ea1i m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c \u0111\u01a1n v\u1ecb. \u2013 S\u1eeda b\u00e0i, c\u00e1c nh\u00f3m thi \u0111ua s\u1eeda ti\u1ebfp s\u1ee9c. + GV h\u1ec7 th\u1ed1ng m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c \u0111\u01a1n v\u1ecb. \u2022 Hai \u0111\u01a1n v\u1ecb \u0111o \u0111\u1ed9 d\u00e0i li\u1ec1n nhau, \u0111\u01a1n v\u1ecb l\u1edbn h\u01a1n g\u1ea5p 10 l\u1ea7n \u0111\u01a1n v\u1ecb b\u00e9 h\u01a1n. \u2022 Hai \u0111\u01a1n v\u1ecb \u0111o di\u1ec7n t\u00edch li\u1ec1n nhau, \u0111\u01a1n v\u1ecb l\u1edbn h\u01a1n g\u1ea5p 100 l\u1ea7n \u0111\u01a1n v\u1ecb b\u00e9 h\u01a1n. + N\u1ebfu HS qu\u00ean m\u1ed1i quan h\u1ec7 gi\u1eefa hai \u0111\u01a1n v\u1ecb kh\u00f4ng li\u1ec1n nhau: \u2022 \u0110\u01a1n v\u1ecb \u0111o \u0111\u1ed9 d\u00e0i: \u00d7 10 \u00d7 10 \u00d7 10 \t m dm cm mm \t : 10 \t\t : 10 : 10 V\u00ed d\u1ee5: \t1 m = .?. mm \t \u2192 \t1 \u00d7 10 \u00d7 10 \u00d7 10 = 1 000 \t \u2192 \t1 m = 1\u2009000 mm \t \t 1 :m1m0 :=10.?.=d1m010 \u2192 \t1 \t \u2192 1 mm = 1 dm 100 Hay: \t 1 dm = 1 \u00d7 10 \u00d7 10 mm = 100 m \t \u2192\t1 mm = 1 dm 100 \u2022 \u0110\u01a1n v\u1ecb \u0111o di\u1ec7n t\u00edch: \u00d7 100 \u00d7 100 \u00d7 100 m2 dm2 cm2 mm2 \t\t : 100 : 100 : 100 V\u00ed d\u1ee5: 1 m2 = .?. cm2 \u2192 1 \u00d7 100 \u00d7 100 = 10 000 \u2192 1 m2 = 10 000 cm2 1 1 cm2 = 10 000 m2 325","B\u00e0i 5: \u2013 HS nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i v\u00e0 th\u1ef1c hi\u1ec7n. \u2013 S\u1eeda b\u00e0i, HS n\u00f3i c\u00e1ch chuy\u1ec3n \u0111\u1ed5i \u0111\u01a1n v\u1ecb. HS c\u00f3 th\u1ec3 chuy\u1ec3n \u0111\u1ed5i theo c\u00e1c c\u00e1ch kh\u00e1c nhau. V\u00ed d\u1ee5: \u2022 145 m = .?. mm + 1 m = 1 ngh\u00ecn mm \u2192 145 m = 145 ngh\u00ecn mm = 145\u2009000 mm (coi ngh\u00ecn l\u00e0 \u0111\u01a1n v\u1ecb \u0111\u1ebfm). + 145 m = 145 \u00d7 1\u2009000 mm = 145\u2009000 mm (nh\u00e2n nh\u1ea9m v\u1edbi 1\u2009000). + D\u1ef1a v\u00e0o quan h\u1ec7 gi\u1eefa hai \u0111\u01a1n v\u1ecb li\u1ec1n nhau, d\u1ef1a v\u00e0o nh\u00e2n nh\u1ea9m v\u1edbi 10. \t m \tdm \tcm \tmm 1 4 \t5 \t0 \t 0 \t 0 \u2192 145 m = 145\u2009000 mm \u2022 10\u2009000 cm2 = .?. m2 + D\u1ef1a v\u00e0o quan h\u1ec7 gi\u1eefa hai \u0111\u01a1n v\u1ecb li\u1ec1n nhau, d\u1ef1a v\u00e0o chia nh\u1ea9m cho 100. m2 dm2 cm2 10 0 0 0 \t \u2192 10\u2009000 cm2 = 1 m2 B\u00e0i 6: \u2013 HS nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i v\u00e0 th\u1ef1c hi\u1ec7n. \u2013 S\u1eeda b\u00e0i, HS th\u00f4ng b\u00e1o k\u1ebft qu\u1ea3, GV kh\u00e1i qu\u00e1t v\u00e0 l\u01b0u \u00fd HS m\u1ed9t s\u1ed1 n\u1ed9i dung. a) \u0110 (Quan h\u1ec7 gi\u1eefa c\u00e1c \u0111\u01a1n v\u1ecb \u0111o kh\u1ed1i l\u01b0\u1ee3ng gi\u1ed1ng quan h\u1ec7 gi\u1eefa c\u00e1c \u0111\u01a1n v\u1ecb \u0111o \u0111\u1ed9 d\u00e0i.) b) S (Quan h\u1ec7 gi\u1eefa c\u00e1c \u0111\u01a1n v\u1ecb \u0111o th\u1eddi gian kh\u00f4ng gi\u1ed1ng quan h\u1ec7 gi\u1eefa c\u00e1c \u0111\u01a1n v\u1ecb \u0111o \u0111\u1ed9 d\u00e0i v\u00e0 kh\u1ed1i l\u01b0\u1ee3ng \u2192 Nh\u1eafc l\u1ea1i m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c \u0111\u01a1n v\u1ecb \u0111o th\u1eddi gian.) c) \u0110 (60 \u00d7 60 = 3\u2009600) d) \u0110 (Nh\u1eadn ra s\u1ef1 t\u01b0\u01a1ng t\u1ef1 gi\u1eefa km v\u00e0 kg, gi\u1eefa mm v\u00e0 ml.) III. V\u1eadn d\u1ee5ng, tr\u1ea3i nghi\u1ec7m B\u00e0i 7: \u2013 Ho\u1ea1t \u0111\u1ed9ng nh\u00f3m. \u2013 C\u00e1c nh\u00f3m t\u00ecm hi\u1ec3u b\u00e0i, nh\u1eadn bi\u1ebft c\u00e1c th\u1eddi \u0111i\u1ec3m v\u00e0 kho\u1ea3ng th\u1eddi gian. Th\u1ea3o lu\u1eadn v\u00e0 t\u00ecm c\u00e1ch GQV\u0110. C\u00f3 th\u1ec3 d\u00f9ng h\u00ecnh v\u1ebd: Th\u00e0nh ph\u1ed1 8 gi\u1edd Th\u00e0nh ph\u1ed1 2 gi\u1edd Th\u00e0nh ph\u1ed1 H\u1ed3 Ch\u00ed Minh H\u00e0 Ti\u00ean Ph\u00fa Qu\u1ed1c 22 gi\u1edd 15 ph\u00fat .?. gi\u1edd .?. ph\u00fat ng\u00e0y 30\/4\/2022 ng\u00e0y .?. \/ .?. \/ .?. 326","HS nh\u1eadn bi\u1ebft: Th\u1eddi \u0111i\u1ec3m xu\u1ea5t ph\u00e1t; \t Kho\u1ea3ng th\u1eddi gian \u0111i; \t T\u00ecm th\u1eddi \u0111i\u1ec3m \u0111\u1ebfn. C\u00e1c nh\u00f3m th\u1ef1c hi\u1ec7n v\u00e0 tr\u00ecnh b\u00e0y. \u2013 S\u1eeda b\u00e0i, c\u00e1c nh\u00f3m c\u00f3 th\u1ec3 c\u00f3 c\u00e1c c\u00e1ch th\u1ef1c hi\u1ec7n kh\u00e1c nhau. GV n\u00ean ch\u1ecdn c\u00e1ch th\u1ee9c gi\u00fap HS d\u1ec5 nh\u1eadn bi\u1ebft. Ch\u1eb3ng h\u1ea1n: + C\u00f3 th\u1ec3 suy lu\u1eadn nh\u01b0 sau: \u00dd A v\u00e0 B sai. (Th\u00e1ng 4 ch\u1ec9 c\u00f3 30 ng\u00e0y.) \u00dd D sai. (T\u1eeb 10 gi\u1edd t\u1ed1i h\u00f4m tr\u01b0\u1edbc t\u1edbi 10 gi\u1edd s\u00e1ng h\u00f4m sau \u0111\u00e3 l\u00e0 12 ti\u1ebfng, t\u1edbi 6 gi\u1edd chi\u1ec1u t\u1ee9c l\u00e0 c\u00f2n th\u00eam n\u1eefa. Trong khi ng\u01b0\u1eddi \u0111\u00f3 ch\u1ec9 \u0111i m\u1ea5t 10 ti\u1ebfng.) \u2192 Ch\u1ecdn C. + N\u1ebfu c\u1ea7n thi\u1ebft, d\u00f9ng h\u00ecnh \u1ea3nh sau \u0111\u1ec3 minh ho\u1ea1. 22 gi\u1edd 15 ph\u00fat 8 gi\u1edd 15 ph\u00fat ng\u00e0y 30\/4\/2022 ng\u00e0y 1\/5\/2022 ng\u00e0y 1\/5\/2022 22 gi\u1edd \t 23 \t 24 \t 1 \t 2 \t 3 \t 4 \t 5 \t 6 \t 7 \t 8 \t 9 \t 10 10 gi\u1edd D\u1ef1a v\u00e0o h\u00ecnh \u1ea3nh tr\u00ean: T\u1eeb 22 gi\u1edd \u2192 th\u00eam 10 gi\u1edd n\u1eefa \u2192 8 gi\u1edd s\u00e1ng h\u00f4m sau \u2192 th\u00eam 15 ph\u00fat \u2192 8 gi\u1edd 15 ph\u00fat ng\u00e0y 1\/5\/2022. B\u00e0i 8: \u2013 HS nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i. Nh\u1eadn d\u1ea1ng \u0111\u01b0\u1ee3c b\u00e0i to\u00e1n \u201ct\u1ed5ng \u2013 hi\u1ec7u\u201d. \u2192 T\u1ed5ng: n\u1eeda chu vi;\t\t\t Hi\u1ec7u: chi\u1ec1u d\u00e0i h\u01a1n chi\u1ec1u r\u1ed9ng. \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n. \u2013 S\u1eeda b\u00e0i, HS tr\u00ecnh b\u00e0y v\u00e0 gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m. \u0110\u1ea5t n\u01b0\u1edbc em \u2013 HS (nh\u00f3m \u0111\u00f4i) \u0111\u1ecdc v\u0103n b\u1ea3n, nh\u1eadn bi\u1ebft c\u00e1c th\u00f4ng tin: + Th\u1eddi gian bay ch\u01b0a \u0111\u1ebfn 1 gi\u1edd. (\u2026 ph\u00fat < 1 gi\u1edd) 2 2 + Th\u1eddi gian bay l\u1edbn h\u01a1n 3 gi\u1edd. ( 3 gi\u1edd < \u2026 ph\u00fat < 1 gi\u1edd) 327","+ Th\u1eddi gian bay l\u00e0 s\u1ed1 tr\u00f2n ch\u1ee5c. ( 2 < ?0 ph\u00fat < 1 gi\u1edd) 3 \u2013 HS th\u1ef1c hi\u1ec7n c\u00e1 nh\u00e2n. \u2013 S\u1eeda b\u00e0i, HS tr\u00ecnh b\u00e0y v\u00e0 gi\u1ea3i th\u00edch c\u00e1ch l\u00e0m. 2 2 1 gi\u1edd = 60 ph\u00fat \u2192 3 gi\u1edd = 60 ph\u00fat \u00d7 3 = 40 ph\u00fat \u2192 40 < s\u1ed1 tr\u00f2n ch\u1ee5c < 60 \u2192 40 < 50 < 60 V\u1eady th\u1eddi gian bay t\u1eeb Th\u00e0nh ph\u1ed1 H\u1ed3 Ch\u00ed Minh \u0111\u1ebfn Ph\u00fa Qu\u1ed1c kho\u1ea3ng 50 ph\u00fat. \u2013 GV c\u00f3 th\u1ec3 t\u00ecm th\u00eam th\u00f4ng tin v\u1ec1 Ph\u00fa Qu\u1ed1c (ph\u00f9 h\u1ee3p v\u1edbi HS) \u0111\u1ec3 gi\u1edbi thi\u1ec7u v\u1edbi c\u00e1c em. V\u00ed d\u1ee5: V\u00f9ng bi\u1ec3n Ph\u00fa Qu\u1ed1c c\u00f3 22 h\u00f2n \u0111\u1ea3o l\u1edbn nh\u1ecf, trong \u0111\u00f3 \u0111\u1ea3o Ph\u00fa Qu\u1ed1c \u0111\u01b0\u1ee3c m\u1ec7nh danh l\u00e0 h\u00f2n \u0111\u1ea3o ng\u1ecdc, c\u00f3 di\u1ec7n t\u00edch l\u1edbn nh\u1ea5t. Ph\u00fa Qu\u1ed1c thu\u1ed9c t\u1ec9nh Ki\u00ean Giang \u2026 Kh\u00e1m ph\u00e1 HS (nh\u00f3m \u0111\u00f4i) \u0111\u1ecdc v\u0103n b\u1ea3n, nh\u1eadn bi\u1ebft c\u00e1c th\u00f4ng tin v\u00e0 tr\u1ea3 l\u1eddi c\u00e2u h\u1ecfi c\u1ee7a b\u00e0i. + Nh\u00e0 h\u00e1t L\u1edbn H\u00e0 N\u1ed9i r\u1ea5t n\u1ed5i ti\u1ebfng. + B\u1eaft \u0111\u1ea7u x\u00e2y d\u1ef1ng t\u1eeb n\u0103m th\u1ee9 nh\u1ea5t c\u1ee7a th\u1ebf k\u1ec9 XX \u2192 N\u0103m 1901. + Sau 10 n\u0103m th\u00ec ho\u00e0n th\u00e0nh \u2192 1901 + 10 = 1911 \u2192 Nh\u00e0 h\u00e1t L\u1edbn H\u00e0 N\u1ed9i \u0111\u00e3 ho\u00e0n th\u00e0nh v\u00e0o n\u0103m 1911. \u00d4N T\u1eacP V\u1ec0 M\u1ed8T S\u1ed0 Y\u1ebeU T\u1ed0 TH\u1ed0NG K\u00ca V\u00c0 X\u00c1C SU\u1ea4T (1 ti\u1ebft) I. Kh\u1edfi \u0111\u1ed9ng Tr\u00f2 ch\u01a1i T\u1eacP T\u1ea6M V\u00d4NG GV cho HS h\u00e1t b\u00e0i \u0111\u1ed3ng dao, n\u00f3i lu\u1eadt ch\u01a1i, t\u1ed5 ch\u1ee9c cho HS ch\u01a1i theo nh\u00f3m \u0111\u00f4i. \u2022 Ng\u01b0\u1eddi \u0111\u1ed1 gi\u1ea5u m\u1ed9t n\u00fat trong l\u00f2ng m\u1ed9t b\u00e0n tay v\u00e0 n\u1eafm c\u1ea3 hai tay l\u1ea1i r\u1ed3i h\u00e1t: \t\t T\u1eadp t\u1ea7m v\u00f4ng \t\t Tay kh\u00f4ng tay c\u00f3 \t\t T\u1eadp t\u1ea7m v\u00f3 \t\t Tay c\u00f3 tay kh\u00f4ng \t\t Tay n\u00e0o c\u00f3, tay n\u00e0o kh\u00f4ng? \u2022 Ng\u01b0\u1eddi \u0111o\u00e1n ch\u1ec9 m\u1ed9t tay c\u1ee7a ng\u01b0\u1eddi \u0111\u1ed1. N\u1ebfu \u0111o\u00e1n \u0111\u00fang, ng\u01b0\u1eddi \u0111o\u00e1n tr\u1edf th\u00e0nh ng\u01b0\u1eddi \u0111\u1ed1, tr\u00f2 ch\u01a1i l\u1ea1i ti\u1ebfp t\u1ee5c. Sau khi ch\u01a1i, GV giu\u0301p HS nh\u00e2\u0323n bi\u00ea\u0301t: \u2022 Khi d\u01b0\u0323 \u0111oa\u0301n, co\u0301 th\u00ea\u0309 \u0111o\u00e1n \u0111\u00fang v\u00e0 c\u0169ng co\u0301 th\u00ea\u0309 \u0111o\u00e1n sai \u2192 C\u00f3 hai kh\u1ea3 n\u0103ng x\u1ea3y ra. II. Th\u1ef1c h\u00e0nh, luy\u1ec7n t\u1eadp B\u00e0i 1: \u2013 HS (nh\u00f3m b\u1ed1n) nh\u1eadn bi\u1ebft y\u00eau c\u1ea7u c\u1ee7a b\u00e0i: Tr\u1ea3 l\u1eddi c\u00e1c c\u00e2u h\u1ecfi. \u2013 Th\u1ea3o lu\u1eadn: Bi\u1ec3u \u0111\u1ed3 n\u00f3i v\u1ec1 g\u00ec? (S\u1ed1 h\u1ecdc sinh c\u00e1c kh\u1ed1i l\u1edbp tham gia h\u1ecdc tr\u1ef1c tuy\u1ebfn.) 328","H\u1ecdc tr\u1ef1c tuy\u1ebfn l\u00e0 g\u00ec? (GV c\u00f3 th\u1ec3 gi\u00fap HS tr\u1ea3 l\u1eddi.) C\u00f3 m\u1ea5y kh\u1ed1i l\u1edbp? M\u1ed7i kh\u1ed1i l\u1edbp c\u00f3 bao nhi\u00eau h\u1ecdc sinh tham gia? (Nh\u00ecn v\u00e0o c\u00e1c s\u1ed1 tr\u00ean c\u00e1c c\u1ed9t m\u00e0u.) \u2013 C\u00e1c nh\u00f3m th\u1ef1c hi\u1ec7n v\u00e0 tr\u00ecnh b\u00e0y. GV h\u1ec7 th\u1ed1ng l\u1ea1i c\u00e1ch l\u00e0m. a) Kh\u1ed1i l\u1edbp 1: 190 h\u1ecdc sinh. Kh\u1ed1i l\u1edbp 2: 214 h\u1ecdc sinh. (nhi\u1ec1u h\u1ecdc sinh tham gia nh\u1ea5t) Kh\u1ed1i l\u1edbp 3: 184 h\u1ecdc sinh. (\u00edt h\u1ecdc sinh tham gia nh\u1ea5t) Kh\u1ed1i l\u1edbp 4: 210 h\u1ecdc sinh. Kh\u1ed1i l\u1edbp 5: 202 h\u1ecdc sinh. b) (190 + 214 + 184 + 210 + 202) : 5 = 200 Trung b\u00ecnh m\u1ed7i kh\u1ed1i l\u1edbp c\u00f3 200 h\u1ecdc sinh h\u1ecdc tr\u1ef1c tuy\u1ebfn. (GV c\u00f3 th\u1ec3 h\u01b0\u1edbng d\u1eabn c\u00e1c em th\u1ef1c hi\u1ec7n vi\u1ec7c t\u00ednh t\u1ed5ng \u0111\u1ec3 tr\u00e1nh tr\u01b0\u1eddng h\u1ee3p c\u00f3 nh\u1edb li\u00ean ti\u1ebfp: 190 + 214 + 184 + 210 + 202 = (100 + 200 + 100 + 200 + 200) + (90 + 10 + 80 + 10) + (4 + 4 + 2) = 800 + 190 + 10 = 990 + 10 = 1\u2009000) III. V\u1eadn d\u1ee5ng, tr\u1ea3i nghi\u1ec7m B\u00e0i 2: \u2013 T\u1ed5 ch\u1ee9c tr\u00f2 ch\u01a1i, m\u1ed7i nh\u00f3m 2 b\u1ea1n. \u2013 M\u1ed7i nh\u00f3m nh\u1eadn bi\u1ebft c\u00e1ch ch\u01a1i. \u2013 Ti\u1ebfn h\u00e0nh ch\u01a1i. + L\u1ea7n l\u01b0\u1ee3t m\u1ed7i b\u1ea1n th\u1ef1c hi\u1ec7n c\u00e1c thao t\u00e1c sau: L\u1ea5y 1 th\u1ebb \u2192 X\u00e1c \u0111\u1ecbnh s\u1ed1 ch\u1eb5n hay l\u1ebb \u2192 N\u1ebfu l\u1ea5y t\u1ea5m th\u1ebb mang s\u1ed1 ch\u1eb5n th\u00ec v\u1ea1ch m\u1ed9t v\u1ea1ch v\u00e0o b\u1ea3ng con \u2192 \u0110\u1eb7t tr\u1ea3 th\u1ebb l\u00ean b\u00e0n, \u00fap th\u1ebb xu\u1ed1ng, tr\u1ed9n c\u00e1c th\u1ebb. + Sau khi m\u1ed7i b\u1ea1n l\u1ea5y th\u1ebb 20 l\u1ea7n \u2192 Ki\u1ec3m \u0111\u1ebfm \u2192 B\u1ea1n n\u00e0o \u0111\u01b0\u1ee3c nhi\u1ec1u v\u1ea1ch h\u01a1n th\u00ec th\u1eafng cu\u1ed9c. \u2013 N\u1ebfu \u0111\u1ed5i y\u00eau c\u1ea7u, c\u00e1c b\u1ea1n s\u1ebd \u0111o\u00e1n (kh\u00f4ng ch\u01a1i) \u2192 GV h\u01b0\u1edbng d\u1eabn HS s\u1eed d\u1ee5ng t\u1eeb \u201cc\u00f3 th\u1ec3\u201d \u0111\u1ec3 di\u1ec5n \u0111\u1ea1t. Ch\u1eb3ng h\u1ea1n: Em c\u00f3 th\u1ec3 th\u1eafng. Em c\u00f3 th\u1ec3 thua. 329","B\u00e0i 79. 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 mua nguy\u00ean li\u1ec7u l\u00e0m s\u1eefa chua cho c\u1ea3 l\u1edbp (ho\u1eb7c cho c\u00e1c b\u1ea1n trong t\u1ed5). \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, dung t\u00edch. \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 v\u00e0 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 trung th\u1ef1c, ch\u0103m ch\u1ec9, tr\u00e1ch nhi\u1ec7m, nh\u00e2n \u00e1i. B. \u0110\u1ed3 d\u00f9ng d\u1ea1y h\u1ecdc HS: C\u00e1c d\u1ee5ng c\u1ee5 \u0111\u1ec3 th\u1ef1c h\u00e0nh trong b\u00e0i. 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 th\u1ef1c h\u00e0nh c\u1ee7a c\u00e1c em. II. Luy\u1ec7n t\u1eadp, th\u1ef1c h\u00e0nh GV c\u00f3 th\u1ec3 cho HS ch\u01a1i: \u201cH\u1ecfi nhanh \u2013 \u0110\u00e1p g\u1ecdn\u201d \u0111\u1ec3 \u00f4n l\u1ea1i c\u00e1ch th\u1ef1c hi\u1ec7n ph\u00e9p nh\u00e2n ph\u00e2n s\u1ed1. III. V\u1eadn d\u1ee5ng, tr\u1ea3i nghi\u1ec7m Ho\u1ea1t \u0111\u1ed9ng theo t\u1ed5. Ho\u1ea1t \u0111\u1ed9ng 1. Chu\u1ea9n b\u1ecb nguy\u00ean li\u1ec7u a) C\u00e1c nh\u00f3m \u0111\u1ecdc k\u0129 c\u00f4ng th\u1ee9c l\u00e0m s\u1eefa chua. \u2013 C\u00f4ng th\u1ee9c n\u00e0y d\u00f9ng \u0111\u1ec3 l\u00e0m bao nhi\u00eau h\u0169 s\u1eefa chua? \u2013 C\u1ea7n m\u1ea5y lo\u1ea1i nguy\u00ean li\u1ec7u? \u2013 S\u1ed1 l\u01b0\u1ee3ng m\u1ed7i lo\u1ea1i nguy\u00ean li\u1ec7u \u0111\u01b0\u1ee3c t\u00ednh theo \u0111\u01a1n v\u1ecb n\u00e0o? b) D\u1ef1 t\u00ednh nguy\u00ean li\u1ec7u \u2013 GV v\u00e0 HS th\u1ed1ng nh\u1ea5t: m\u1ed7i t\u1ed5 \u0111\u1ec1u l\u00e0m s\u1eefa chua cho c\u1ea3 l\u1edbp hay ch\u1ec9 l\u00e0m cho c\u00e1c b\u1ea1n trong t\u1ed5. \u2013 Tu\u1ef3 thu\u1ed9c v\u00e0o quy\u1ebft \u0111\u1ecbnh tr\u00ean \u0111\u1ec3 d\u1ef1 t\u00ednh nguy\u00ean li\u1ec7u. + M\u1ed7i t\u1ed5 s\u1ebd l\u00e0m bao nhi\u00eau h\u0169 s\u1eefa chua? + D\u1ef1 t\u00ednh nguy\u00ean li\u1ec7u c\u1ee5 th\u1ec3: S\u1eefa \u0111\u1eb7c c\u00f3 \u0111\u01b0\u1eddng: \u2026 h\u1ed9p. S\u1eefa chua c\u00e1i: \u2026 h\u1ed9p. S\u1eefa t\u01b0\u01a1i c\u00f3 v\u1ecb d\u00e2u: \u2026 ml. N\u01b0\u1edbc l\u1ecdc: \u2026 l. 330","\u2013 GV gi\u00fap c\u00e1c nh\u00f3m t\u00ecm hi\u1ec3u th\u00f4ng tin tr\u00ean m\u1ea1ng Internet: + Mua c\u00e1c nguy\u00ean li\u1ec7u v\u1edbi nh\u00e3n hi\u1ec7u n\u00e0o. + Gi\u00e1 ti\u1ec1n m\u1ed7i lo\u1ea1i nhi\u00ean li\u1ec7u l\u00e0 bao nhi\u00eau. + GV gi\u00fap c\u00e1c nh\u00f3m t\u00ednh t\u1ed5ng s\u1ed1 ti\u1ec1n \u0111\u1ec3 mua nguy\u00ean li\u1ec7u. + Th\u1ed1ng nh\u1ea5t ngu\u1ed3n ti\u1ec1n s\u1eed d\u1ee5ng (ch\u1eb3ng h\u1ea1n: ti\u1ec1n qu\u1ef9 l\u1edbp c\u00f3 \u0111\u01b0\u1ee3c nh\u1edd k\u1ebf ho\u1ea1ch nh\u1ecf, \u2026). \u2013 GV l\u00ean k\u1ebf ho\u1ea1ch \u0111\u01b0a c\u00e1c nh\u00f3m \u0111i mua nguy\u00ean li\u1ec7u v\u00e0o m\u1ed9t ng\u00e0y c\u1ee5 th\u1ec3 n\u00e0o \u0111\u00f3. (Nguy\u00ean v\u1eadt li\u1ec7u \u0111\u00e3 mua s\u1ebd \u0111\u1ec3 nh\u1edd \u1edf t\u1ee7 l\u1ea1nh n\u00e0o?) c) Ph\u00e2n c\u00f4ng chu\u1ea9n b\u1ecb v\u1eadt li\u1ec7u l\u00e0m s\u1eefa chua \u2013 C\u00e1c v\u1eadt li\u1ec7u ph\u00f9 h\u1ee3p s\u1ed1 l\u01b0\u1ee3ng h\u0169 s\u1eefa chua m\u00e0 t\u1ed5 l\u00e0m. \u2013 Ph\u00e2n c\u00f4ng c\u1ee5 th\u1ec3 c\u00e1c b\u1ea1n chu\u1ea9n b\u1ecb d\u1ee5ng c\u1ee5. \u2013 Th\u1ed1ng nh\u1ea5t ng\u00e0y, gi\u1edd l\u00e0m s\u1eefa chua (n\u00ean l\u00e0m v\u00e0o c\u00e1c bu\u1ed5i h\u1ecdc ngo\u1ea1i kho\u00e1). Ho\u1ea1t \u0111\u1ed9ng 2. L\u00e0m s\u1eefa chua C\u00e1c nh\u00f3m l\u00e0m theo h\u01b0\u1edbng d\u1eabn trong b\u00e0i. N\u1ed9i dung n\u00e0o ch\u01b0a r\u00f5 th\u00ec GV gi\u1ea3i th\u00edch. \u2013 GV v\u00e0 HS th\u1eadt ch\u00fa \u00fd v\u1ec1 an to\u00e0n, c\u1ea9n th\u1eadn khi s\u1eed d\u1ee5ng n\u01b0\u1edbc s\u00f4i. \u2013 GV b\u1ed1 tr\u00ed n\u01a1i HS \u0111\u1ec3 c\u00e1c th\u00f9ng s\u1eefa chua sau khi l\u00e0m xong. \u2013 GV nh\u1edd ng\u01b0\u1eddi c\u1ea5t c\u00e1c h\u0169 s\u1eefa chua th\u00e0nh ph\u1ea9m v\u00e0o t\u1ee7 l\u1ea1nh. \u2013 Th\u1ed1ng nh\u1ea5t ng\u00e0y, gi\u1edd th\u01b0\u1edfng th\u1ee9c s\u1eefa chua \u2192 T\u1ed5 n\u00e0o l\u00e0m ngon nh\u1ea5t? Ho\u1ea1t \u0111\u1ed9ng th\u1ef1c t\u1ebf C\u00f9ng ng\u01b0\u1eddi th\u00e2n l\u00e0m s\u1eefa chua (c\u00f3 th\u1ec3 theo c\u00f4ng th\u1ee9c c\u1ee7a gia \u0111\u00ecnh). \u2013 T\u1eadp t\u00ednh l\u01b0\u1ee3ng nguy\u00ean li\u1ec7u. \u2013 T\u00ednh ti\u1ec1n mua nguy\u00ean li\u1ec7u. \u2013 S\u1eeda so\u1ea1n d\u1ee5ng c\u1ee5 l\u00e0m s\u1eefa chua. \u2013 Gi\u00fap ng\u01b0\u1eddi th\u00e2n ti\u1ebfn h\u00e0nh l\u00e0m s\u1eefa chua. \u2013 C\u1ea3 nh\u00e0 c\u00f9ng th\u01b0\u1edfng th\u1ee9c. 331","KI\u1ec2M TRA CU\u1ed0I N\u0102M (1 ti\u1ebft) 1. Khoanh v\u00e0o ch\u1eef c\u00e1i tr\u01b0\u1edbc \u00fd tr\u1ea3 l\u1eddi \u0111\u00fang. a) S\u1ed1 g\u1ed3m 7 tri\u1ec7u, 5 tr\u0103m ngh\u00ecn, 6 ch\u1ee5c ngh\u00ecn v\u00e0 8 \u0111\u01a1n v\u1ecb \u0111\u01b0\u1ee3c vi\u1ebft l\u00e0: A. 756\u2009008 \tB. 7\u2009560\u2009008 \t C. 7 568 000 \t D. 7 000 568 b) Ch\u1eef s\u1ed1 4 trong l\u1edbp ngh\u00ecn c\u1ee7a s\u1ed1 24 054 344 c\u00f3 gi\u00e1 tr\u1ecb l\u00e0: A. 4 tri\u1ec7u \tB. 4 ngh\u00ecn \t C. 4 ch\u1ee5c \t D. 4 \u0111\u01a1n v\u1ecb c) S\u1ed1 li\u1ec1n sau c\u1ee7a s\u1ed1 9\u2009999 l\u00e0: A. 1 000 \tB. 9\u2009998 \t C. 10\u2009000 \t D. 100\u2009000 d) S\u1ed1 th\u1ee9 m\u01b0\u1eddi trong d\u00e3y s\u1ed1 140; 142; 144; \u2026 l\u00e0: A. S\u1ed1 l\u1ebb \tB. S\u1ed1 ch\u1eb5n \t C. S\u1ed1 tr\u00f2n ch\u1ee5c \t D. S\u1ed1 tr\u00f2n tr\u0103m 2. \u0110\u00fang ghi \u0110 , sai ghi S . a) 3 gi\u1edd 25 ph\u00fat = 205 ph\u00fat. b) Di\u1ec7n t\u00edch c\u1ee7a h\u00ecnh ch\u1eef nh\u1eadt c\u00f3 chi\u1ec1u d\u00e0i 2 m, chi\u1ec1u r\u1ed9ng 1 m l\u00e0 2 m. 33 3. \u0110\u1eb7t t\u00ednh r\u1ed3i t\u00ednh. a) 28 745 + 9 106 b) 317 \u00d7 24 4. T\u00ednh. b) 4 \u00d7 5 \u2013 4 \u00d7 2 a) 250 \u00d7 7 \u00d7 5 \u00d7 4 \u00d7 20 27 3 27 3 5. Gi\u1ea3i b\u00e0i to\u00e1n sau. Ng\u01b0\u1eddi ta \u0111\u1ed5 3 can d\u1ea7u, m\u1ed7i can ch\u1ee9a 5 l v\u00e0o \u0111\u1ea7y c\u00e1c chai r\u1ed7ng, m\u1ed7i chai ch\u1ee9a \u0111\u01b0\u1ee3c 3 l 4 d\u1ea7u. Sau \u0111\u00f3 c\u1ee9 12 chai d\u1ea7u l\u1ea1i x\u1ebfp v\u00e0o 1 h\u1ed9p. H\u1ecfi c\u1ea7n \u00edt nh\u1ea5t bao nhi\u00eau h\u1ed9p \u0111\u1ec3 \u0111\u1ef1ng h\u1ebft t\u1ea5t c\u1ea3 s\u1ed1 chai d\u1ea7u \u0111\u00f3? 6. \u0110i\u1ec1n c\u00e1c t\u1eeb: C\u00f3 th\u1ec3, ch\u1eafc ch\u1eafn hay kh\u00f4ng th\u1ec3 v\u00e0o ch\u1ed7 ch\u1ea5m. C\u00f4 gi\u00e1o th\u00f4ng b\u00e1o: \u201cNg\u00e0y mai, l\u1edbp ch\u00fang ta s\u1ebd \u0111\u00f3n m\u1ed9t b\u1ea1n m\u1edbi\u201d. B\u1ea1n \u0111\u00f3 \u2026\u2026\u2026\u2026\u2026\u2026 l\u00e0 b\u1ea1n nam nh\u01b0ng c\u0169ng \u2026\u2026\u2026\u2026\u2026\u2026 l\u00e0 b\u1ea1n n\u1eef. 332","HU\u00c2N CH\u01af\u01a0NG H\u1ed2 CH\u00cd MINH TR\u1ea6N NAM D\u0168NG (T\u1ed5\u00adng Ch\u1ee7 bi\u00ean) B\u1ed8 S\u00c1CH GI\u00c1O VI\u00caN L\u1edaP 4 \u2013 CH\u00c2N TR\u1edcI S\u00c1NG T\u1ea0O 1. TI\u1ebeNG VI\u1ec6T 4 \u2013 T\u1eacP M\u1ed8T 8. TIN H\u1eccC 4 TO\u00c1N 4 \u2022 S\u00e1ch gi\u00e1o vi\u00ean S\u00e1ch gi\u00e1o vi\u00ean S\u00e1ch gi\u00e1o vi\u00ean 2. TI\u1ebeNG VI\u1ec6T 4 \u2013 T\u1eacP HAI 9. C\u00d4NG NGH\u1ec6 4 S\u00e1ch gi\u00e1o vi\u00ean S\u00e1ch gi\u00e1o vi\u00ean 3. TO\u00c1N 4 10. GI\u00c1O D\u1ee4C TH\u1ec2 CH\u1ea4T 4 S\u00e1ch gi\u00e1o vi\u00ean S\u00e1ch gi\u00e1o vi\u00ean 4. TI\u1ebeNG ANH 4 Family and Friends 11. \u00c2M NH\u1ea0C 4 (National Edition) \u2013 Teacher's Guide S\u00e1ch gi\u00e1o vi\u00ean 5. \u0110\u1ea0O \u0110\u1ee8C 4 12. M\u0128 THU\u1eacT 4 (B\u1ea2N 1) S\u00e1ch gi\u00e1o vi\u00ean S\u00e1ch gi\u00e1o vi\u00ean 6. KHOA H\u1eccC 4 13. M\u0128 THU\u1eacT 4 (B\u1ea2N 2) S\u00e1ch gi\u00e1o vi\u00ean S\u00e1ch gi\u00e1o vi\u00ean 7. L\u1ecaCH S\u1eec V\u00c0 \u0110\u1ecaA L\u00cd 4 14. HO\u1ea0T \u0110\u1ed8NG TR\u1ea2I NGHI\u1ec6M 4 (B\u1ea2N 1) S\u00e1ch gi\u00e1o vi\u00ean S\u00e1ch gi\u00e1o vi\u00ean 15. HO\u1ea0T \u0110\u1ed8NG TR\u1ea2I NGHI\u1ec6M 4 (B\u1ea2N 2) S\u00e1ch gi\u00e1o vi\u00ean C\u00e1c \u0111\u01a1n v\u1ecb \u0111\u1ea7u m\u1ed1i ph\u00e1t h\u00e0nh \u2022 Mi\u1ec1n B\u1eafc: CTCP \u0110\u1ea7u t\u01b0 v\u00e0 Ph\u00e1t tri\u1ec3n Gi\u00e1o d\u1ee5c H\u00e0 N\u1ed9i CTCP S\u00e1ch v\u00e0 Thi\u1ebft b\u1ecb Gi\u00e1o d\u1ee5c mi\u1ec1n B\u1eafc \u2022 Mi\u1ec1n Trung: CTCP \u0110\u1ea7u t\u01b0 v\u00e0 Ph\u00e1t tri\u1ec3n Gi\u00e1o d\u1ee5c \u0110\u00e0 N\u1eb5ng CTCP S\u00e1ch v\u00e0 Thi\u1ebft b\u1ecb Gi\u00e1o d\u1ee5c mi\u1ec1n Trung \u2022 Mi\u1ec1n Nam: CTCP \u0110\u1ea7u t\u01b0 v\u00e0 Ph\u00e1t tri\u1ec3n Gi\u00e1o d\u1ee5c Ph\u01b0\u01a1ng Nam CTCP S\u00e1ch v\u00e0 Thi\u1ebft b\u1ecb Gi\u00e1o d\u1ee5c mi\u1ec1n Nam CTCP S\u00e1ch v\u00e0 Thi\u1ebft b\u1ecb Gi\u00e1o d\u1ee5c C\u1eedu Long S\u00e1ch \u0111i\u1ec7n t\u1eed: http:\/\/hanhtrangso.nxbgd.vn K\u00edch ho\u1ea1t \u0111\u1ec3 m\u1edf h\u1ecdc li\u1ec7u \u0111i\u1ec7n t\u1eed: C\u00e0o l\u1edbp nh\u0169 tr\u00ean tem \u0111\u1ec3 nh\u1eadn m\u00e3 s\u1ed1. Truy c\u1eadp http:\/\/hanhtrangso.nxbgd.vn v\u00e0 nh\u1eadp m\u00e3 s\u1ed1 t\u1ea1i bi\u1ec3u t\u01b0\u1ee3ng ch\u00eca kho\u00e1. Gi\u00e1: ....... \u0111"]