460 bai toan vui luyen tri thong minh

["C\u00e2u 1: \u0110\u00e1p s\u1ed1: B\u1eadt c\u1ea3 hai c\u00f4ng t\u1eafc. C\u00e2u 2: B\u00e0i gi\u1ea3i: Sau khi d\u1eddi, s\u1ed1 s\u00e1ch m\u1ed7i ng\u0103n c\u00f3 l\u00e0: 98 : 2 = 49 (cu\u1ed1n) S\u1ed1 s\u00e1ch ban \u0111\u1ea7u ng\u0103n nh\u1ea5t c\u00f3 l\u00e0: 49 + 12 = 61 (cu\u1ed1n) S\u1ed1 s\u00e1ch ban \u0111\u1ea7u ng\u0103n hai c\u00f3 l\u00e0: 49 - 12 = 37 (cu\u1ed1n) \u0110\u00e1p s\u1ed1: Ng\u0103n th\u1ee9 nh\u1ea5t: 61 cu\u1ed1n, ng\u0103n th\u1ee9 hai: 37 cu\u1ed1n. C\u00e2u 3: B\u00e0i gi\u1ea3i: C\u00e1ch 1: 4 ng\u00e0y \u0111\u1ea7u \u0111\u1eafp \u0111\u01b0\u1ee3c: 115 x 4 = 460 ( m3) 6 ng\u00e0y sau \u0111\u1eafp \u0111\u01b0\u1ee3c:","140 x 6 = 840 ( m3) S\u1ed1 \u0111\u1ea5t \u0111\u00e3 \u0111\u1eafp \u0111\u01b0\u1ee3c l\u00e0: 460 + 840 = 1.300 ( m3) S\u1ed1 ng\u00e0y l\u00e0m vi\u1ec7c l\u00e0: 4 + 6 = 10 (ng\u00e0y) Trung b\u00ecnh m\u1ed7i ng\u00e0y \u0111\u1eafp \u0111\u01b0\u1ee3c: 1.300 : 10 = 130 ( m3) C\u00e1ch 2: S\u1ed1 m\u00e9t kh\u1ed1i \u0111\u1ea5t \u0111\u00e3 \u0111\u1eafp \u0111\u01b0\u1ee3c l\u00e0: 115 x 4 + 140 x 6 = 1.300 ( m3) Trung b\u00ecnh m\u1ed7i ng\u00e0y \u0111\u1eafp \u0111\u01b0\u1ee3c: 1.300 : (4 + 6) = 130 ( m3) \u0110\u00e1p s\u1ed1: 130 m3. C\u00e2u 4: \u0110\u00e1p s\u1ed1: 7 gi\u1edd 20 ph\u00fat. H\u01b0\u1edbng d\u1eabn: - T\u00ecm th\u1ec3 t\u00edch b\u1ec3 n\u01b0\u1edbc. - T\u00ecm xem m\u1ed7i ph\u00fat b\u1ec3 c\u00f3 th\u00eam bao nhi\u00eau l\u00edt n\u01b0\u1edbc? - T\u00ednh th\u1eddi gian \u0111\u1ec3 n\u01b0\u1edbc ch\u1ea3y \u0111\u1ea7y b\u1ec3. - T\u00ednh xem b\u1ec3 \u0111\u1ea7y n\u01b0\u1edbc l\u00fac n\u00e0o?","C\u00e2u 5: \u0110\u00e1p s\u1ed1: 6 S\u1ed1 tr\u01b0\u1edbc h\u01a1n s\u1ed1 sau 7 \u0111\u01a1n v\u1ecb.","B\u00e0i 27 C\u00e2u 1: \u0110\u00e1p s\u1ed1: H\u00ecnh 3. C\u00e2u 2: \u0110\u00e1p s\u1ed1: Ch\u1ec9 c\u00f2n l\u1ea1i 1 con b\u1ecb b\u1eafn ch\u1ebft n\u1eb1m \u0111\u00f3 th\u00f4i, c\u00f2n c\u00e1c con kh\u00e1c nghe ti\u1ebfng n\u1ed5 s\u1ebd ch\u1ea1y \u0111i m\u1ea5t. C\u00e2u 3: \u0110\u00e1p s\u1ed1: 12 gi\u1edd 7,5 ph\u00fat. C\u00e2u 4: \u0110\u00e1p s\u1ed1: 42 Ch\u1eef s\u1ed1 h\u00e0ng Ch\u1eef s\u1ed1 h\u00e0ng \u0111\u01a1n S\u1ed1 c\u00f3 hai ch\u1eef S\u1ed1 c\u00f3 hai ch\u1eef s\u1ed1 tr\u1eeb K\u1ebft ch\u1ee5c v\u1ecb s\u1ed1 \u0111i qu\u1ea3 Sai 1 2 12 8 Sai 2 4 24 20 Sai 3 6 36 32 \u0110\u00fang 4 8 48 44 B\u1ea3ng tr\u00ean l\u00e0 k\u1ebft qu\u1ea3 th\u1ed1ng k\u00ea t\u1ea5t c\u1ea3 c\u00e1c tr\u01b0\u1eddng h\u1ee3p c\u00f3 th\u1ec3 x\u1ea3y ra c\u1ee7a b\u00e0i to\u00e1n. V\u00ec 5 x 2 = 10 l\u00e0 s\u1ed1 c\u00f3 hai ch\u1eef s\u1ed1 n\u00ean ta ch\u1ec9 c\u00f3 4 tr\u01b0\u1eddng h\u1ee3p. Trong \u0111\u00f3, ba tr\u01b0\u1eddng h\u1ee3p \u0111\u1ec1u b\u1ecb lo\u1ea1i v\u00ec \u1edf c\u1ed9t 4 kh\u00f4ng cho c\u00e1c s\u1ed1 c\u00f3 hai ch\u1eef s\u1ed1 gi\u1ed1ng nhau. Ri\u00eang tr\u01b0\u1eddng h\u1ee3p cu\u1ed1i \u0111\u01b0\u1ee3c ch\u1ea5p nh\u1eadn, v\u00ec 44 g\u1ed3m hai ch\u1eef s\u1ed1 gi\u1ed1ng nhau. V\u1eady \u0111\u00e1p s\u1ed1 l\u00e0 48.","C\u00e2u 5: B\u00e0i gi\u1ea3i: Vi\u1ebft t\u1eaft kh\u1ed1i l\u01b0\u1ee3ng c\u1ee7a m\u1ed7i con g\u00e0 l\u00e0 g\u00e0 v\u00e0 kh\u1ed1i l\u01b0\u1ee3ng c\u1ee7a m\u1ed7i con v\u1ecbt l\u00e0 v\u1ecbt. Ta c\u00f3: 4 v\u1ecbt - 6 g\u00e0 = 1 (kg) hay 12 v\u1ecbt - 18 g\u00e0 = 3 (kg) 10 g\u00e0 - 3 v\u1ecbt = 7,5 (kg) hay 40 g\u00e0 - 12 v\u1ecbt = 30 (kg) V\u1eady: 40 - 18 = 22 (con g\u00e0) th\u00ec n\u1eb7ng: 30 + 3 = 33 (kg) M\u1ed7i con g\u00e0 n\u1eb7ng: 33 : 22 = 1,5 (kg) 4 con v\u1ecbt n\u1eb7ng: 6 x 1,5 + 1 = 10 (kg) M\u1ed7i con v\u1ecbt n\u1eb7ng: 10 : 4 = 2,5 (kg) \u0110\u00e1p s\u1ed1: V\u1ecbt: 2,5 kg. C\u00e2u 6: \u0110\u00e1p s\u1ed1: d. 4 C\u00e2u 7: \u0110\u00e1p s\u1ed1: 31 T\u1ed5ng c\u00e1c s\u1ed1 \u1edf m\u1ed7i c\u1ed9t l\u00e0 36","C\u00e2u 8: \u0110\u00e1p s\u1ed1: 4\/3 T\u00edch hai s\u1ed1 li\u1ec1n nhau, r\u1ed3i tu\u1ea7n t\u1ef1 chia cho 1, 2, 3, 4 s\u1ebd \u0111\u01b0\u1ee3c s\u1ed1 k\u1ebf ti\u1ebfp \u0111\u1eb1ng sau V\u00ed d\u1ee5: ? 3 4 6 8 12 ? x 3 : 1 = 4 \u21d2 ? = 4\/3 3 x 4 : 2 = 12 : 2 = 6 ... C\u00e2u 9: B\u00e0i gi\u1ea3i: S\u1ed1 c\u1edd c\u1ea7n d\u00f9ng l\u00e0: 210 : 3 = 71 (c\u1edd) S\u1ed1 v\u1ea3i may c\u1edd l\u00e0: 12 x 71 = 852 (dm) hay 85,2m \u0110\u00e1p s\u1ed1: 85,2m. C\u00e2u 10: B\u00e0i gi\u1ea3i: S\u1ed1 v\u1edf m\u1ed7i b\u1ea1n \u0111\u01b0\u1ee3c th\u01b0\u1edfng l\u00e0: 5 + 3 = 8 (quy\u1ec3n) S\u1ed1 v\u1edf c\u00f4 \u0111em ph\u00e1t th\u01b0\u1edfng l\u00e0: 8 x 5 = 40 (quy\u1ec3n)","Ch\u00fa \u00fd: Ta c\u00f3 th\u1ec3 gi\u1ea3i gh\u00e9p nh\u01b0 sau: S\u1ed1 v\u1edf \u0111em ph\u00e1t th\u01b0\u1edfng c\u00f3 t\u1ea5t c\u1ea3 l\u00e0: (5 + 3) x 5 = 40 (quy\u1ec3n) \u0110\u00e1p s\u1ed1: 40 quy\u1ec3n.","C\u00e2u 1: S\u1ed1 ch\u00e2n ng\u01b0\u1eddi l\u00e0: 5 x 2 = 10 (ch\u00e2n) S\u1ed1 m\u00e8o c\u00f3 l\u00e0: ( 1 + 5 ) x 5 = 30 (con m\u00e8o) S\u1ed1 ch\u00e2n m\u00e8o c\u00f3 l\u00e0: 30 x 4 = 120 (ch\u00e2n) V\u1eady tr\u00ean \u0111\u01b0\u1eddng c\u00f3 t\u1ed5ng s\u1ed1 ch\u00e2n l\u00e0: 10 + 120 = 130 (ch\u00e2n) \u0110\u00e1p s\u1ed1: 130 c\u00e1i ch\u00e2n. C\u00e2u 2: \u0110\u00e1p s\u1ed1: H\u00ecnh C. C\u00e2u 3: B\u00e0i gi\u1ea3i: S\u1ed1 b\u1ea1n nam t\u00f3c h\u00fai c\u00f3 l\u00e0: 42 - 30 = 12 (b\u1ea1n) S\u1ed1 t\u1ed5 b\u1ea1n nam c\u00f3 l\u00e0:","12 : 6 = 2 (t\u1ed5) \u0110\u00e1p s\u1ed1: 2 t\u1ed5. C\u00e2u 4: \u0110\u00e1p s\u1ed1: Hai cha, hai con ngh\u0129a l\u00e0 \u00f4ng, cha v\u00e0 ch\u00e1u, th\u00ec r\u00f5 l\u00e0 c\u00f3 3 ng\u01b0\u1eddi r\u1ed3i. M\u1ed7i ng\u01b0\u1eddi c\u00e2u \u0111\u01b0\u1ee3c 1 con c\u00e1 th\u00ec v\u1ec1 nh\u00e0 c\u00f3 3 con l\u00e0 \u0111\u00fang. C\u00e2u 5: \u0110\u00e1p s\u1ed1: ? = 12 6 x 0,5 = 0,25 x 12 C\u00e2u 6: \u0110\u00e1p s\u1ed1: 46 S\u1ed1 tr\u01b0\u1edbc tr\u1eeb \u0111i s\u1ed1 \u0111\u1ee9ng li\u1ec1n sau n\u00f3 \u0111\u01b0\u1ee3c k\u1ebft qu\u1ea3 l\u1ea7n l\u01b0\u1ee3t l\u00e0: 11, 22, 33, 44 C\u00e2u 7: B\u00e0i gi\u1ea3i: Khi T\u00e8o ra ch\u1ee3 th\u00ec s\u1ed1 tr\u1ee9ng c\u00f2n l\u1ea1i l\u00e0: 10 - 1 - 2 = 7 (qu\u1ea3) T\u00e8o b\u00e1n \u0111\u01b0\u1ee3c s\u1ed1 ti\u1ec1n l\u00e0: 1.500 x 7 = 10.500 (\u0111\u1ed3ng) \u0110\u00e1p s\u1ed1: 10.500 (\u0111\u1ed3ng).","C\u00e2u 8: a. 60 h\u00ecnh ch\u1eef nh\u1eadt Tr\u00ean h\u00ecnh v\u1ebd c\u00f3 4 \u0111\u01b0\u1eddng th\u1eb3ng song song n\u1eb1m ngang v\u00e0 5 \u0111\u01b0\u1eddng th\u1eb3ng song song th\u1eb3ng \u0111\u1ee9ng. Ta th\u1ea5y c\u1ee9 m\u1ed9t c\u1eb7p \u0111\u01b0\u1eddng th\u1eb3ng n\u1eb1m ngang v\u00e0 1 c\u1eb7p \u0111\u01b0\u1eddng th\u1eb3ng \u0111\u1ee9ng th\u00ec t\u1ea1o th\u00e0nh m\u1ed9t h\u00ecnh ch\u1eef nh\u1eadt. 4 \u0111\u01b0\u1eddng th\u1eb3ng n\u1eb1m ngang s\u1ebd t\u1ea1o th\u00e0nh: 4 x (4 - 1) : 2 = 6 (c\u1eb7p \u0111\u01b0\u1eddng th\u1eb3ng n\u1eb1m ngang) 5 \u0111\u01b0\u1eddng th\u1eb3ng \u0111\u1ee9ng s\u1ebd t\u1ea1o th\u00e0nh: 5 x (5 - 1 ) : 2 = 10 (c\u1eb7p \u0111\u01b0\u1eddng th\u1eb3ng n\u1eb1m \u0111\u1ee9ng) Ta th\u1ea5y: C\u1ee9 c\u1eb7p \u0111\u01b0\u1eddng th\u1eb3ng n\u1eb1m ngang v\u1edbi m\u1ed9t c\u1eb7p \u0111\u01b0\u1eddng th\u1eb3ng \u0111\u1ee9ng t\u1ea1o th\u00e0nh 1 h\u00ecnh ch\u1eef nh\u1eadt 6 c\u1eb7p \u0111\u01b0\u1eddng th\u1eb3ng n\u1eb1m ngang v\u1edbi m\u1ed9t c\u1eb7p \u0111\u01b0\u1eddng th\u1eb3ng \u0111\u1ee9ng t\u1ea1o th\u00e0nh 6 h\u00ecnh ch\u1eef nh\u1eadt. - V\u1eady 6 c\u1eb7p \u0111\u01b0\u1eddng th\u1eb3ng n\u1eb1m ngang v\u1edbi 10 c\u1eb7p \u0111\u01b0\u1eddng th\u1eb3ng \u0111\u1ee9ng s\u1ebd t\u1ea1o th\u00e0nh: 6 x 10 = 60 (h\u00ecnh ch\u1eef nh\u1eadt) b. 120cm v\u00e0 54cm2","12 3 4 87 6 5 9 10 11 12 C\u00f3 12 h\u00ecnh vu\u00f4ng l\u00e0 12 \u00f4 vu\u00f4ng 12 h\u00ecnh vu\u00f4ng \u0111\u00f3 c\u00f3 t\u1ed5ng chu vi v\u00e0 t\u1ed5ng di\u1ec7n t\u00edch l\u00e0: (1 x 4) x 12 = 48 (cm) (1 x 1) x 12 = 12 (cm2 ) C\u00f3 6 h\u00ecnh vu\u00f4ng m\u00e0 m\u1ed7i h\u00ecnh g\u1ed3m 4 \u00f4 vu\u00f4ng l\u00e0 c\u00e1c h\u00ecnh (1, 2, 7, 8) ; (2, 3, 6, 7) ; (3, 4, 5, 6) ; (8, 7, 10, 9) ; (7, 6, 11, 10) ; (6, 5, 12, 11). 6 h\u00ecnh vu\u00f4ng n\u00e0y c\u00f3 t\u1ed5ng chu vi v\u00e0 t\u1ed5ng di\u1ec7n t\u00edch l\u00e0: (2 x 4) x 6 = 48 (cm) (2 x 2 ) x 6 = 24 (cm2 ) C\u00f3 hai h\u00ecnh vu\u00f4ng m\u00e0 m\u1ed7i h\u00ecnh g\u1ed3m 9 \u00f4 vu\u00f4ng l\u00e0: (1, 2, 3, 6, 7, 8, 9, 10, 11) ; (2, 3, 4, 5, 6, 7, 10, 11, 12) t\u1ed5ng chu vi v\u00e0 t\u1ed5ng di\u1ec7n t\u00edch c\u1ee7a ch\u00fang l\u00e0: (3 x 4) x 2 = 24 (cm) (3 x 3) x 2 = 18 (cm2 ) V\u1eady t\u1ed5ng chu vi t\u1ea5t c\u1ea3 c\u00e1c h\u00ecnh vu\u00f4ng \u1edf \u0111\u00e2y l\u00e0: 48 + 48 + 24 = 120 (cm) C\u00f2n t\u1ed5ng di\u1ec7n t\u00edch t\u1ea5t c\u1ea3 c\u00e1c h\u00ecnh vu\u00f4ng \u1edf \u0111\u00e2y l\u00e0: 12 + 24 + 18 = 54 (cm2 )","C\u00e2u 9: \u0110\u00e1p s\u1ed1: \u0110ang l\u00e0 ban ng\u00e0y th\u00ec l\u00e0m sao \u00f4ng T\u00e2y \u0111en b\u1ecb \u0111\u00e2m v\u00e0o \u00f4t\u00f4 \u0111\u01b0\u1ee3c. C\u00e2u 10: B\u00e0i gi\u1ea3i: S\u1ed1 bi c\u1ee7a m\u1ed7i ng\u01b0\u1eddi sau khi cho l\u00e0: 48 : 2 = 24 (vi\u00ean bi) S\u1ed1 bi c\u1ee7a B\u00ed tr\u01b0\u1edbc khi cho l\u00e0: 24 + (3 - 1) = 26 (vi\u00ean bi) S\u1ed1 bi c\u1ee7a B\u1ea7u tr\u01b0\u1edbc khi cho l\u00e0: 48 - 26 = 22 (vi\u00ean bi) \u0110\u00e1p s\u1ed1: B\u00ed c\u00f3 26 vi\u00ean bi, B\u1ea7u c\u00f3 22 vi\u00ean bi","B\u00e0i 29 C\u00e2u 1: B\u00e0i gi\u1ea3i: a) 30 con b\u00f2 lo\u1ea1i m\u1ed9t m\u1ed7i n\u0103m cho s\u1ed1 s\u1eefa l\u00e0: 4.000 x 30 = 120.000 (l) S\u1ed1 b\u00f2 lo\u1ea1i hai trong tr\u1ea1i; 100 - 30 = 70 (con) 70 con b\u00f2 lo\u1ea1i hai m\u1ed7i n\u0103m cho m\u1ed9t s\u1ed1 s\u1eefa l\u00e0: 3.600 x 70 = 252.000 (l) T\u1ed5ng s\u1ed1 s\u1eefa tr\u1ea1i thu \u0111\u01b0\u1ee3c trong m\u1ed9t n\u0103m: 120.000 + 252.000 = 372.000 (l) Trung b\u00ecnh m\u1ed7i n\u0103m 1 con b\u00f2 cho m\u1ed9t s\u1ed1 s\u1eefa: 372.000 : 100 = 3720 (l) b) Trung b\u00ecnh m\u1ed7i con trong m\u1ed9t th\u00e1ng cho m\u1ed9t s\u1ed1 s\u1eefa: 3.720 : 12 = 310 (l) \u0110\u00e1p s\u1ed1: a. 3.720 l\u00edt b. 310 l\u00edt. C\u00e2u 2: \u0110\u00e1p s\u1ed1: H\u00ecnh e","C\u00e2u 3: \u0110\u00e1p s\u1ed1: 105 ng\u00e0y c\u00f4ng. C\u00e2u 4: \u0110\u00e1p s\u1ed1: Ch\u1eb3ng m\u1ea5t \u0111i \u0111\u00e2u c\u1ea3. 3 b\u00e1t ph\u1edf l\u00e0 25.000\u0111, c\u1ed9ng v\u1edbi 3.000\u0111 tr\u1ea3 l\u1ea1i v\u1edbi 2.000\u0111 anh h\u1ea7u b\u00e0n l\u1ea5y \u0111i m\u1ea5t. V\u1eady t\u1ed5ng s\u1ed1 ti\u1ec1n l\u00e0 30.000 \u0111\u1ed3ng. C\u00e2u 5: \u0110\u00e1p s\u1ed1: 256 H\u00e0ng ngang tr\u00ean s\u1ed1 tr\u01b0\u1edbc nh\u00e2n 2 ra s\u1ed1 \u0111\u1ee9ng li\u1ec1n sau. H\u00e0ng ngang d\u01b0\u1edbi s\u1ed1 tr\u01b0\u1edbc nh\u00e2n v\u1edbi ch\u00ednh n\u00f3 ra s\u1ed1 \u0111\u1ee9ng li\u1ec1n sau. C\u00e2u 6: B\u00e0i gi\u1ea3i: C\u00e1ch 1: S\u1ed1 b\u1ea1n b\u1edbt ra \u1edf m\u1ed7i b\u00e0n l\u00e0: 6 - 4 = 2 (b\u1ea1n) S\u1ed1 b\u1ea1n b\u1edbt ra \u1edf 8 b\u00e0n l\u00e0: 2 x 8 = 16 (b\u1ea1n) S\u1ed1 b\u00e0n c\u1ea7n k\u00ea th\u00eam l\u00e0: 16 : 4 = 4 (b\u00e0n) C\u00e1ch 2: S\u0129 s\u1ed1 h\u1ecdc sinh l\u1edbp em l\u00e0:","6 x 8 = 48 (b\u1ea1n) M\u1ed7i b\u00e0n 4 b\u1ea1n th\u00ec s\u1ed1 b\u00e0n c\u1ea7n c\u00f3 l\u00e0: 48 : 4 = 12 (b\u00e0n) S\u1ed1 b\u00e0n c\u1ea7n k\u00ea th\u00eam l\u00e0: 12 - 8 = 4 (b\u00e0n) \u0110\u00e1p s\u1ed1: 4 b\u00e0n. C\u00e2u 7: \u0110\u00e1p s\u1ed1: 10 30 + 70 = 100 10 + 90 = 100 C\u00e2u 8: \u0110\u00e1p s\u1ed1: H\u00ecnh 4 C\u00e2u 9: \u0110\u00e1p s\u1ed1: R\u00fat tr\u01b0\u1edbc hay r\u00fat sau \u0111\u00e2u quan tr\u1ecdng, c\u01a1 h\u1ed9i cho c\u1ea3 3 ng\u01b0\u1eddi \u0111\u1ec1u l\u00e0 1\/3.","C\u00e2u 1: \u0110\u00e1p s\u1ed1: 1,25 km. \u0110i l\u00ean d\u1ed1c 1km th\u00ec h\u1ebft: 60 : 2,5 = 24 (ph\u00fat) \u0110i xu\u1ed1ng d\u1ed1c 1km th\u00ec h\u1ebft: 60 : 5 = 12 (ph\u00fat) V\u1eady m\u1ed7i km \u0111\u01b0\u1eddng c\u1ea3 \u0111i l\u1eabn v\u1ec1 h\u1ebft t\u1ea5t c\u1ea3: 24 + 12 = 36 (ph\u00fat) Qu\u00e3ng \u0111\u01b0\u1eddng AB d\u00e0i: (21 + 24) : 36 = 1,25 (km) C\u00e2u 2: \u0110\u00e1p s\u1ed1: B = 36, F = 55, W = 21 B = 8 + 7 + 8 + 6 + 7 = 36 F = 8 + 7 + 6 + 7 + 8 + 6 + 6 + 7 = 55 W = 7 + 6 +8 = 21 C\u00e2u 3: \u0110\u00e1p s\u1ed1: 98","C\u00e1c s\u1ed1 \u1edf c\u1ed9t 1 l\u1ea7n l\u01b0\u1ee3t nh\u00e2n v\u1edbi 5, c\u1ed9t 2 nh\u00e2n v\u1edbi 6, c\u1ed9t 3 nh\u00e2n v\u1edbi 7, c\u1ed9t 4 nh\u00e2n v\u1edbi 8 14 x 7 = 98 C\u00e2u 4: \u0110\u00e1p s\u1ed1: 150, 15 v\u00e0 60 Theo \u0111\u1ea7u b\u00e0i th\u00ec s\u1ed1 th\u1ee9 nh\u1ea5t l\u1edbn g\u1ea5p 10 l\u1ea7n s\u1ed1 th\u1ee9 hai v\u00e0 t\u1ed5ng ba s\u1ed1 l\u00e0: 75 x 3 = 225 Ta c\u00f3 s\u01a1 \u0111\u1ed3: So v\u1edbi s\u1ed1 th\u1ee9 hai th\u00ec 225 g\u1ea5p: 1 + 10 + 4 = 15 (l\u1ea7n) S\u1ed1 th\u1ee9 hai l\u00e0: 225 : 15 = 15 S\u1ed1 th\u1ee9 nh\u1ea5t l\u00e0: 150 S\u1ed1 th\u1ee9 ba l\u00e0: 15 x 4 = 60 C\u00e2u 5: \u0110\u00e1p s\u1ed1: 12 h\u00ecnh ch\u1eef nh\u1eadt","C\u00e2u 6: \u0110\u00e1p s\u1ed1: 3 b\u1ea1n v\u00e0 17 quy\u1ec3n v\u1edf. S\u1ed1 v\u1edf \u0111\u1ee7 \u0111\u1ec3 chia cho m\u1ed7i b\u1ea1n 6 quy\u1ec3n nhi\u1ec1u h\u01a1n s\u1ed1 v\u1edf \u0111\u1ee7 \u0111\u1ec3 chia cho m\u1ed7i b\u1ea1n 5 quy\u1ec3n l\u00e0: 2 + 1 = 3 (quy\u1ec3n) S\u1ed1 v\u1edf m\u1ed7i b\u1ea1n \u0111\u01b0\u1ee3c chia 6 quy\u1ec3n nhi\u1ec1u h\u01a1n s\u1ed1 v\u1edf m\u1ed7i b\u1ea1n \u0111\u01b0\u1ee3c chia 5 quy\u1ec3n l\u00e0: 6 - 5 = 1 (quy\u1ec3n) V\u1eady s\u1ed1 b\u1ea1n c\u00f3 l\u00e0: 3 : 1 = 3 (b\u1ea1n) S\u1ed1 v\u1edf l\u00e0: 3 x 5 + 2 = 17 (quy\u1ec3n) C\u00e2u 7: \u0110\u00e1p s\u1ed1: 62 tu\u1ed5i. Tu\u1ed5i m\u1eb9 l\u00e0: 33 - 2 = 31 (tu\u1ed5i) Tu\u1ed5i b\u00e0 l\u00e0: 31 x 2 = 62 (tu\u1ed5i) Ch\u00fa \u00fd: Ta c\u00f3 th\u1ec3 gh\u00e9p nh\u01b0 sau: Tu\u1ed5i b\u00e0 l\u00e0: (33 - 2) x 2 = 62 (tu\u1ed5i).","C\u00e2u 8: \u0110\u00e1p s\u1ed1: K. Theo b\u1ea3ng ch\u1eef c\u00e1i t\u1eeb A \u21d2 Z Ta th\u1ea5y: T\u1eeb I ti\u1ebfn t\u1edbi A l\u00e0 9 \u0111\u01a1n v\u1ecb. E gi\u1eadt l\u00f9i v\u1ec1 Z l\u00e0 22 \u0111\u01a1n v\u1ecb. \u21d2 9 + 22 = 31 T\u01b0\u01a1ng t\u1ef1 nh\u01b0 v\u1eady ta \u0111\u01b0\u1ee3c ch\u1eef c\u00e1i K. C\u00e2u 9: \u0110\u00e1p s\u1ed1: 14,4 ; 12 v\u00e0 9,6 C\u00e1ch 1: a. S\u1ed1 th\u1ee9 nh\u1ea5t nh\u00e2n v\u1edbi 10 b\u1eb1ng s\u1ed1 b\u00e9 nh\u1ea5t nh\u00e2n v\u1edbi 15. V\u1eady n\u1ebfu s\u1ed1 l\u1edbn nh\u1ea5t g\u1ed3m 15 ph\u1ea7n b\u1eb1ng nhau th\u00ec s\u1ed1 b\u00e9 nh\u1ea5t g\u1ed3m 10 ph\u1ea7n b\u1eb1ng nhau \u1ea5y: b. Ta c\u00f3 s\u01a1 \u0111\u1ed3: V\u1eady s\u1ed1 l\u1edbn nh\u1ea5t l\u00e0: 4,8 : (15 - 10) x 15 = 4,8 x 15 : 5 = 14,4 S\u1ed1 b\u00e9 nh\u1ea5t l\u00e0:","14,4 - 4,8 = 9,6 Suy ra s\u1ed1 l\u1edbn th\u1ee9 hai l\u00e0: 14,4 x 10 : 12 = 12 C\u00e1ch 2: L\u00ed lu\u1eadn nh\u01b0 ph\u1ea7n (a) \u1edf c\u00e1ch 1 r\u1ed3i l\u00e0m ti\u1ebfp nh\u01b0 sau: V\u00ec 15\/10 = 3\/2 n\u00ean c\u0169ng c\u00f3 th\u1ec3 n\u00f3i: n\u1ebfu s\u1ed1 l\u1edbn nh\u1ea5t g\u1ed3m 3 ph\u1ea7n b\u1eb1ng nhau th\u00ec s\u1ed1 nh\u1ecf nh\u1ea5t g\u1ed3m 2 ph\u1ea7n b\u1eb1ng nhau \u1ea5y. M\u1ed9t ph\u1ea7n b\u1eb1ng nhau ch\u00eanh l\u1ec7ch \u1edf \u0111\u00e2y ch\u00ednh l\u00e0 hi\u1ec7u c\u1ee7a hai s\u1ed1 \u0111\u00f3. V\u1eady 1 ph\u1ea7n b\u1eb1ng nhau l\u00e0 4,8. Suy ra: S\u1ed1 l\u1edbn nh\u1ea5t l\u00e0: 4,8 x 3 = 14,4 S\u1ed1 b\u00e9 nh\u1ea5t l\u00e0: 4,8 x 2 = 9,6 (ho\u1eb7c 14,4 - 4,8 = 9,6) V\u1eady s\u1ed1 th\u1ee9 hai l\u00e0: 14,4 x 10 : 12 = 12 ho\u1eb7c: 9,6 x 15 : 12 = 12 C\u00e2u 10: \u0110\u00e1p s\u1ed1: 44 em. S\u1ed1 em c\u00f3 trong m\u1ed7i t\u1ed5 l\u00e0: 5 + 6 = 11 (em) S\u0129 s\u1ed1 l\u1edbp em l\u00e0: 11 x 4 = 44 (em)","B\u00e0i 31 C\u00e2u 1: \u0110\u00e1p s\u1ed1 : 7 T\u1ed5ng c\u00e1c s\u1ed1 \u1edf h\u00e0ng ngang l\u00e0 45 C\u00e2u 2: \u0110\u00e1p s\u1ed1: 8 th\u00f9ng v\u00e0 12 th\u00f9ng. V\u00ec s\u1ed1 d\u1ea7u \u0111\u1ef1ng \u1edf m\u1ed7i lo\u1ea1i th\u00f9ng \u0111\u1ec1u b\u1eb1ng nhau n\u00ean s\u1ee9c ch\u1ee9a (dung t\u00edch) c\u1ee7a c\u00e1c th\u00f9ng v\u00e0 s\u1ed1 th\u00f9ng t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi nhau. Lo\u1ea1i th\u00f9ng 60 l\u00edt c\u00f3 dung t\u00edch g\u1ea5p r\u01b0\u1ee1i lo\u1ea1i th\u00f9ng 40 l\u00edt n\u00ean s\u1ed1 th\u00f9ng 40 l\u00edt ph\u1ea3i nhi\u1ec1u g\u1ea5p r\u01b0\u1ee1i th\u00f9ng 60 l\u00edt. Ta c\u00f3 s\u01a1 \u0111\u1ed3: M\u1ed7i \u201cx\u201d b\u1eb1ng nhau g\u1ed3m: 20 : (2 + 3) = 4 (th\u00f9ng) S\u1ed1 th\u00f9ng 60 l\u00edt l\u00e0: 4 x 2 = 8 (th\u00f9ng) S\u1ed1 th\u00f9ng 40 l\u00edt l\u00e0: 4 x 3 = 12 (th\u00f9ng)","C\u00e2u 3: \u0110\u00e1p s\u1ed1: 15 S\u1ed1 b\u1ecb chia : 5 = th\u01b0\u01a1ng V\u1eady s\u1ed1 b\u1ecb chia g\u1ea5p 5 l\u1ea7n th\u01b0\u01a1ng S\u1ed1 b\u1ecb chia + s\u1ed1 chia + th\u01b0\u01a1ng = 95 S\u1ed1 b\u1ecb chia + 5 + th\u01b0\u01a1ng = 95 T\u1ed5ng s\u1ed1 b\u1ecb chia v\u00e0 th\u01b0\u01a1ng l\u00e0: 95 - 5 = 90 T\u1ed5ng s\u1ed1 ph\u1ea7n b\u1eb1ng nhau l\u00e0: 1 + 5 = 6 (ph\u1ea7n) Th\u01b0\u01a1ng l\u00e0: 90 : 6 = 15 C\u00e2u 4: \u0110\u00e1p s\u1ed1: K = 47, L = 18, M = 32 K= 6 + 5 + 6 + 5 + 5 + 6 + 7 + 7 = 47 L= 7 + 6 + 5= 18 M= 5 + 6 + 7 + 7 + 7= 32 C\u00e2u 5: \u0110\u00e1p s\u1ed1: 13 h\u00ecnh.","C\u00e2u 6: \u0110\u00e1p s\u1ed1: 3 c\u00e2y v\u00e0 4 con chim. C\u00e2u 7: \u0110\u00e1p s\u1ed1: 12,25m v\u00e0 8,75m. Gi\u00e1 ti\u1ec1n 1m v\u1ea3i l\u00e0: 315.000 : 21 = 15.000 (\u0111) Ng\u01b0\u1eddi th\u1ee9 nh\u1ea5t mua nhi\u1ec1u h\u01a1n ng\u01b0\u1eddi th\u1ee9 hai: 52.500 : 15.000 = 3,5 (m) Ng\u01b0\u1eddi th\u1ee9 nh\u1ea5t \u0111\u00e3 mua: (21 + 3,5) : 2 = 12,25 (m) Ng\u01b0\u1eddi th\u1ee9 hai \u0111\u00e3 mua: 12,25 - 3,5 = 8,75 (m) C\u00e2u 8: \u0110\u00e1p s\u1ed1: 73 C\u00e2u 9: \u0110\u00e1p s\u1ed1: b. 177 C\u00e2u 10: A=B So s\u00e1nh A v\u00e0 B","A = 155 + 50dm A = 155 + 5m A = 160m B = 1km - 840m B = 1000m - 840m B = 160m","C\u00e2u 1: \u0110\u00e1p s\u1ed1: 23, 25 v\u00e0 27 M\u1ed7i s\u1ed1 l\u1ebb h\u01a1n k\u00e9m nhau 2 \u0111\u01a1n v\u1ecb. Ba l\u1ea7n s\u1ed1 l\u1ebb th\u1ee9 nh\u1ea5t l\u00e0: 75 - (2 + 2 + 2) = 69 V\u1eady s\u1ed1 l\u1ebb th\u1ee9 nh\u1ea5t l\u00e0: 69 : 3 = 23 S\u1ed1 l\u1ebb th\u1ee9 hai v\u00e0 ba l\u00e0 25 v\u00e0 27 Ch\u00fa \u00fd: C\u00f3 th\u1ec3 suy lu\u1eadn c\u00e1ch kh\u00e1c nh\u01b0 sau: D\u1ec5 d\u00e0ng nh\u1eadn th\u1ea5y t\u1ed5ng c\u1ee7a 3 s\u1ed1 l\u1ebb li\u00ean ti\u1ebfp g\u1ea5p 3 l\u1ea7n s\u1ed1 l\u1ebb \u1edf gi\u1eefa. V\u1eady s\u1ed1 l\u1ebb \u1edf gi\u1eefa l\u00e0: 75 : 3 = 25 V\u00e0 ta c\u0169ng c\u00f3 \u0111\u00e1p s\u1ed1: 23, 25 v\u00e0 27 C\u00e2u 2: B\u00e0i gi\u1ea3i: V\u1edbi s\u1ed1 g\u1ea1o \u0111\u00f3, n\u1ebfu \u0103n h\u1ebft trong 1 ng\u00e0y th\u00ec s\u1ed1 ng\u01b0\u1eddi \u0103n l\u00e0: 120 x 50 = 6.000 (ng\u01b0\u1eddi) V\u1edbi s\u1ed1 g\u1ea1o \u0111\u00f3, n\u1ebfu \u0103n h\u1ebft trong 30 ng\u00e0y th\u00ec s\u1ed1 ng\u01b0\u1eddi \u0103n l\u00e0:","6.000 : 30 = 200 (ng\u01b0\u1eddi) V\u1eady s\u1ed1 ng\u01b0\u1eddi \u0111\u1ebfn th\u00eam l\u00e0: 200 - 120 = 80 (ng\u01b0\u1eddi) \u0110\u00e1p s\u1ed1: 80 ng\u01b0\u1eddi C\u00e2u 3: \u0110\u00e1p s\u1ed1: 7 S\u1ed1 \u1edf h\u00e0ng th\u1ee9 nh\u1ea5t tr\u1eeb \u0111i s\u1ed1 \u1edf h\u00e0ng th\u1ee9 hai \u0111\u1ec3 cho ra s\u1ed1 h\u00e0ng th\u1ee9 ba. C\u00e2u 4: \u0110\u00e1p s\u1ed1: d.12 h\u00ecnh tam gi\u00e1c. C\u00e2u 5: B\u00e0i gi\u1ea3i: C\u1ea3 hai b\u00e1c \u0111\u00e3 l\u00e0m trong: 24 + 21 = 45 (ng\u00e0y) Ti\u1ec1n c\u00f4ng c\u1ee7a m\u1ed7i ng\u00e0y l\u00e0: 1.350.000 : 45 = 30.000 (\u0111) B\u00e1c An \u0111\u01b0\u1ee3c s\u1ed1 ti\u1ec1n l\u00e0: 24 x 30.000 = 720.000 (\u0111) B\u00e1c Th\u1ecbnh \u0111\u01b0\u1ee3c s\u1ed1 ti\u1ec1n l\u00e0: 21 x 30.000 = 630.000 (\u0111) \u0110\u00e1p s\u1ed1: 720.000\u0111 v\u00e0 630.000\u0111.","C\u00e2u 6: \u0110\u00e1p s\u1ed1: 13 C\u00e2u 7: B\u00e0i gi\u1ea3i: Theo \u0111\u1ea7u b\u00e0i th\u00ec s\u1ed1 h\u1ecdc sinh ph\u1ea3i chia h\u1ebft cho 7 (v\u00ec 6 + 1 = 7). T\u1eeb 40 \u0111\u1ebfn 50 ch\u1ec9 c\u00f3 42 v\u00e0 49 chia h\u1ebft cho 7 n\u00ean s\u1ed1 h\u1ecdc sinh ch\u1ec9 c\u00f3 th\u1ec3 l\u00e0 42 ho\u1eb7c 49. Song s\u1ed1 h\u1ecdc sinh l\u1ea1i l\u00e0 s\u1ed1 ch\u1eb5n (v\u00ec chia \u0111\u00f4i \u0111\u01b0\u1ee3c) n\u00ean s\u1ed1 \u0111\u00f3 l\u00e0 42 V\u1eady s\u1ed1 h\u1ecdc sinh kh\u00f4ng \u0111\u01b0\u1ee3c bi\u1ec3u d\u01b0\u01a1ng l\u00e0: 42 : 7 = 6 (h\u1ecdc sinh) Suy ra s\u1ed1 h\u1ecdc sinh \u0111\u01b0\u1ee3c bi\u1ec3u d\u01b0\u01a1ng l\u00e0: 6 x 6 = 36 (h\u1ecdc sinh) \u0110\u00e1p s\u1ed1: 36 h\u1ecdc sinh. C\u00e2u 8: B\u00e0i gi\u1ea3i: S\u0129 s\u1ed1 l\u1edbp em l\u00e0: 20 + 27 = 47 (b\u1ea1n) S\u1ed1 b\u1ea1n x\u1ebfp chung m\u1ed7i h\u00e0ng l\u00e0: 47 : 4 = 11 (b\u1ea1n) d\u01b0 3 b\u1ea1n V\u1eady c\u00f3 3 b\u1ea1n c\u1ea7m c\u1edd \u0111i tr\u01b0\u1edbc. \u0110\u00e1p s\u1ed1: a: 11 b\u1ea1n, b: 3 b\u1ea1n.","B\u00e0i 33 C\u00e2u 1: \u0110\u00e1p s\u1ed1: d. Nhi\u1ec1u c\u00e1ch C\u00e2u 2: B\u00e0i gi\u1ea3i: S\u1ed1 gh\u1ebf c\u00f3 t\u1ea5t c\u1ea3 l\u00e0: 24 + 36 = 60 (gh\u1ebf) S\u1ed1 b\u00e0n c\u00f3 l\u00e0: 60 : 4 = 15 (b\u00e0n) \u0110\u00e1p \u00e1n: 60 gh\u1ebf v\u00e0 15 b\u00e0n. C\u00e2u 3: \u0110\u00e1p s\u1ed1: b. 9 C\u00e2u 4: \u0110\u00e1p s\u1ed1: 90 s\u1ed1. C\u00e1c s\u1ed1 c\u00f3 ba ch\u1eef s\u1ed1 t\u1eadn c\u00f9ng b\u1eb1ng 5 l\u00e0: 105, 115, 125..., 985, 995 Trong d\u00e3y s\u1ed1 tr\u00ean kho\u1ea3ng c\u00e1ch gi\u1eefa hai s\u1ed1 li\u00ean ti\u1ebfp lu\u00f4n lu\u00f4n l\u00e0 10 \u0111\u01a1n v\u1ecb.","T\u1eeb 105 \u0111\u1ebfn 995 c\u00f3: (995 - 105) : 10 = 89 (kho\u1ea3ng c\u00e1ch) nh\u01b0 v\u1eady Do \u0111\u00f3 d\u00e3y tr\u00ean ta c\u00f3: 89 + 1 = 90 (s\u1ed1) C\u00e2u 5: \u0110\u00e1p s\u1ed1: 18 S\u1ed1 sau b\u1eb1ng s\u1ed1 tr\u01b0\u1edbc + 3 15 + 3 = 18 C\u00e2u 6: \u0110\u00e1p s\u1ed1: b. 1\/24.000 C\u00e2u 7: B\u00e0i gi\u1ea3i 1 ng\u01b0\u1eddi ph\u1ea3i b\u1eaft tay: 10 - 1 = 9 (c\u00e1i) 10 ng\u01b0\u1eddi ph\u1ea3i b\u1eaft tay: 10 x 9 = 90 (c\u00e1i) Nh\u01b0ng n\u1ebfu t\u00ednh nh\u01b0 v\u1eady th\u00ec m\u1ed7i c\u00e1i b\u1eaft tay \u0111\u1ec1u \u0111\u01b0\u1ee3c t\u00ednh hai l\u1ea7n. V\u1eady th\u1ef1c ra ch\u1ec9 c\u00f3: 90 : 2 = 45 (c\u00e1i) Ch\u00fa \u00fd:","C\u00f3 th\u1ec3 gi\u1ea3i b\u00e0i to\u00e1n b\u1eb1ng d\u00e3y t\u00ednh sau: 10 x (10 - 1) : 2 = 45 (c\u00e1i b\u1eaft tay) \u0110\u00e1p s\u1ed1: 45 (c\u00e1i b\u1eaft tay)","C\u00e2u 1: \u0110\u00e1p s\u1ed1: H\u00ecnh C. C\u00e2u 2: \u0110\u00e1p s\u1ed1: \u0110\u00fang. C\u00e2u 3: H\u01b0\u1edbng d\u1eabn Tr\u01b0\u1eddng h\u1ee3p 1: ch\u1ecdn 3 nam v\u00e0 4 n\u1eef Tr\u01b0\u1eddng h\u1ee3p 2: ch\u1ecdn 4 nam v\u00e0 3 n\u1eef Tr\u01b0\u1eddng h\u1ee3p 3: ch\u1ecdn 5 nam v\u00e0 2 n\u1eef C\u1ed9ng c\u1ea3 3 tr\u01b0\u1eddng h\u1ee3p l\u1ea1i l\u00e0 ra \u0111\u00e1p \u00e1n. C\u00e2u 4: \u0110\u00e1p s\u1ed1: 18 s\u1ed1. \u0110\u00f3 l\u00e0 c\u00e1c s\u1ed1: 1230 2130 3120 1203 2103 3102 1320 2310 3210 1302 2301 3201","1023 2013 3012 1032 2031 3021 C\u00e2u 5: \u0110\u00e1p s\u1ed1: 15 L\u1ea5y c\u1ed9t th\u1ee9 nh\u1ea5t nh\u00e2n c\u1ed9t th\u1ee9 hai r\u1ed3i tr\u1eeb c\u1ed9t th\u1ee9 ba (7 x 3) - 6 = 15 C\u00e2u 6: 888 + 88 + 8 + 8 + 8 = 1000 C\u00e2u 7: \u0110\u00e1p s\u1ed1: 2 h\u00ecnh G v\u00e0 H kh\u00f4ng theo quy lu\u1eadt v\u1edbi c\u00e1c h\u00ecnh c\u00f2n l\u1ea1i. C\u00e2u 8: \u0110\u00e1p s\u1ed1: OOXXXXXXXX","B\u00e0i 35 C\u00e2u 1: \u0110\u00e1p s\u1ed1: a. M\u1ed9t c\u00e2y l\u1edbn (th\u1ef1c t\u1ebf l\u00e0 m\u1ed9t qu\u00e2n nh\u00e9p l\u1edbn). B\u1ee9c h\u00ecnh n\u00e0y \u0111\u01b0\u1ee3c t\u1ea1o n\u00ean t\u1eeb m\u1ed9t qu\u00e2n nh\u00e9p trong b\u1ed9 t\u00fa l\u01a1 kh\u01a1. C\u00e2u 2: \u0110\u00e1p s\u1ed1: 15 S\u1ed1 sau h\u01a1n s\u1ed1 tr\u01b0\u1edbc 2 \u0111\u01a1n v\u1ecb. C\u00e2u 3: B\u00e0i gi\u1ea3i: S\u1ed1 sao m\u1ed7i b\u1ea1n nam x\u1ebfp \u0111\u01b0\u1ee3c l\u00e0: 10 - 3 = 7 (sao) S\u1ed1 sao 19 b\u1ea1n nam x\u1ebfp \u0111\u01b0\u1ee3c l\u00e0: 7 x 19 = 133 (sao) Ch\u00fa \u00fd: Ta c\u00f3 th\u1ec3 gi\u1ea3 gh\u00e9p nh\u01b0 sau: S\u1ed1 sao 19 b\u1ea1n nam x\u1ebfp \u0111\u01b0\u1ee3c l\u00e0: (10 - 3) x 19 = 133 ( sao) \u0110\u00e1p s\u1ed1: 133 sao. C\u00e2u 4:","\u0110\u00e1p s\u1ed1: 14 h\u00ecnh vu\u00f4ng. C\u00e2u 5: \u0110\u00e1p s\u1ed1: 4 ng\u01b0\u1eddi con v\u00e0 24 c\u00e1i k\u1eb9o. S\u1ed1 k\u1eb9o m\u1ed7i ng\u01b0\u1eddi con \u0111\u01b0\u1ee3c chia th\u00eam: 8 - 6 = 2 (c\u00e1i) Ph\u1ea7n c\u1ee7a anh c\u1ea3 6 c\u00e1i, nay chia th\u00eam cho m\u1ed7i ng\u01b0\u1eddi 2 c\u00e1i, n\u00ean s\u1ed1 ng\u01b0\u1eddi \u0111\u01b0\u1ee3c chia th\u00eam k\u1eb9o l\u00e0: 6 : 2 = 3 (ng\u01b0\u1eddi) S\u1ed1 con trong gia \u0111\u00ecnh l\u00e0: 3 + 1 = 4 (ng\u01b0\u1eddi) S\u1ed1 k\u1eb9o c\u1ee7a m\u1eb9 l\u00e0: 6 x 4 = 24 (c\u00e1i) C\u00e2u 6: \u0110\u00e1p s\u1ed1: C\u00f4 \u0110\u1ecf t\u00f3c m\u00e0u \u0111en. C\u00e2u 7: \u0110\u00e1p s\u1ed1: b. 5219 qu\u1ea3. C\u00e2u 8: \u0110\u00e1p s\u1ed1: Ng\u00e0y h\u00f4m qua c\u1ee7a ng\u00e0y mai l\u00e0 th\u1ee9 Ba t\u1ee9c ng\u00e0y h\u00f4m qua l\u00e0 th\u1ee9 T\u01b0, ng\u00e0y mai l\u00e0 ng\u00e0y h\u00f4m qua c\u1ee7a th\u1ee9 B\u1ea3y t\u1ee9c ng\u00e0y mai l\u00e0 th\u1ee9 S\u00e1u. V\u1eady ng\u00e0y h\u00f4m nay l\u00e0 th\u1ee9 N\u0103m.","C\u00e2u 9: 1 \u0111\u1ed3ng = 10 h\u00e0o = 100 xu Th\u1ebf n\u00ean l\u00e0m sao 100 xu = 10 \u0111\u1ed3ng \u0111\u01b0\u1ee3c. Nh\u01b0 v\u1eady l\u00e0 sai.","C\u00e2u 1: \u0110\u00e1p s\u1ed1: 7 L\u1ea5y s\u1ed1 \u1edf h\u00e0ng 1 tr\u1eeb \u0111i s\u1ed1 \u1edf h\u00e0ng 2 r\u1ed3i chia cho s\u1ed1 \u1edf h\u00e0ng 3. C\u00e2u 2: \u0110\u00e1p s\u1ed1: 36 G\u1ecdi X l\u00e0 s\u1ed1 ti\u1ec1n m\u1ed7i n\u1eafm. Theo \u0111\u1ec1 b\u00e0i ta c\u00f3 ph\u01b0\u01a1ng tr\u00ecnh: X + X + 1\/2X + 1\/4X + 1 = 100 Gi\u1ea3i ph\u01b0\u01a1ng tr\u00ecnh ta \u0111\u01b0\u1ee3c X = 36 C\u00e2u 3: \u0110\u00e1p s\u1ed1: Ng\u01b0\u1eddi th\u1ee9 ba t\u00ean l\u00e0 H\u00f9ng. C\u00e2u 4: \u0110\u00e1p s\u1ed1: Lo\u1ea1i I : 3.200\u0111 Lo\u1ea1i II : 2.400\u0111 Lo\u1ea1i III : 2.000\u0111 C\u00e2u 5:","a\/ 8 = 2 x 2 x 2 b\/ 27 = 3 x 3 x 3 c\/ 16 = 4 x 4 16 = 2 x 2 x 2 x 2 d\/ 100 = 10 x 10 C\u00e2u 6: \u0110\u00e1p s\u1ed1: 10 T\u1ea5t c\u1ea3 c\u00e1c c\u1ed9t c\u1ed9ng l\u1ea1i v\u1edbi nhau th\u00e0nh 30. C\u00e2u 7: B\u00e0i gi\u1ea3i: M\u1ed9t th\u00f9ng \u0111\u1ef1ng \u0111\u01b0\u1ee3c: 27 : 3 = 9 (l\u00edt) S\u1ed1 th\u00f9ng t\u1ea5t c\u1ea3 l\u00e0: 12 + 5 = 17 (th\u00f9ng) S\u1ed1 l\u00edt m\u1eadt ong l\u00e0: 17 x 9 = 153 (l\u00edt) \u0110\u00e1p s\u1ed1: 153 l\u00edt m\u1eadt ong. C\u00e2u 8: B\u00e0i gi\u1ea3i: \u0110\u1ed5i 5 quy\u1ec3n s\u00e1ch l\u1ea5y 5 quy\u1ec3n v\u1edf th\u00ec b\u1edbt \u0111\u01b0\u1ee3c:","5.500 x 5 = 27.500 (\u0111) Do \u0111\u00f3 ta ch\u1ec9 ph\u1ea3i tr\u1ea3: 43.500 - 27.500 = 16.000 (\u0111) V\u1eady 16.000\u0111 l\u00e0 gi\u00e1 c\u1ee7a: 5 + 3 = 8 (quy\u1ec3n v\u1edf) G\u00e1i 1 quy\u1ec3n v\u1edf l\u00e0: 16.000 : 8 = 2.000 (\u0111) Gi\u00e1 m\u1ed9t quy\u1ec3n s\u00e1ch l\u00e0: 2.000 + 5.500 = 7.500 (\u0111) \u0110\u00e1p s\u1ed1: 1 quy\u1ec3n s\u00e1ch: 7.500\u0111, 1 quy\u1ec3n v\u1edf: 2.000\u0111.","B\u00e0i 37 C\u00e2u 1: \u0110\u00e1p s\u1ed1: C\u00e1c s\u1ed1 2 ch\u1eef s\u1ed1 c\u00f3 ch\u1eef s\u1ed1 h\u00e0ng ch\u1ee5c b\u1eb1ng ch\u1eef s\u1ed1 h\u00e0ng \u0111\u01a1n v\u1ecb l\u00e0: 11, 22, 33, 44, 55, 66, 77, 88, 99 C\u00e2u 2: \u0110\u00e1p s\u1ed1: J = 48, K = 32, L = 18 J = 6 + 4 + 8 + 4 + 4 + 8 + 6 + 8 = 48 K = 6 + 8 + 8 + 6 + 4 = 32 L = 6 + 4 + 8 = 18 C\u00e2u 3: \u0110\u00e1p s\u1ed1: a. 3 v\u00e0 12 C\u00e2u 4: B\u00e0i gi\u1ea3i: C\u00e1ch 1: 4 ng\u00e0y \u0111\u1ea7u \u0111\u1eafp \u0111\u01b0\u1ee3c: 115 x 4 = 460 ( m3) 6 ng\u00e0y sau \u0111\u1eafp \u0111\u01b0\u1ee3c:","140 x 6 = 840 ( m3) S\u1ed1 \u0111\u1ea5t \u0111\u1eafp \u0111\u01b0\u1ee3c l\u00e0: 460 + 840 = 1.300 ( m3) S\u1ed1 ng\u00e0y l\u00e0m vi\u1ec7c l\u00e0: 4 + 6 = 10 (ng\u00e0y) Trung b\u00ecnh m\u1ed7i ng\u00e0y \u0111\u1eafp \u0111\u01b0\u1ee3c: 1.300 : 10 = 130 ( m3) C\u00e1ch 2: S\u1ed1 m3 \u0111\u1ea5t \u0111\u00e3 \u0111\u1eafp \u0111\u01b0\u1ee3c l\u00e0: 115 x 4 + 140 x 6 = 1.300 ( m3) Trung b\u00ecnh m\u1ed7i ng\u00e0y \u0111\u1eafp \u0111\u01b0\u1ee3c: 1.300 : (4 + 6) = 130 ( m3) \u0110\u00e1p s\u1ed1: 130 m3. C\u00e2u 5: B\u00e0i gi\u1ea3i: C\u00e1ch 1: S\u1ed1 ti\u1ec3u \u0111\u1ed9i c\u00f3 l\u00e0: 900 : 15 = 60 (ti\u1ec3u \u0111\u1ed9i) S\u1ed1 trung \u0111\u1ed9i c\u00f3 l\u00e0: 60 : 4 = 15 (trung \u0111\u1ed9i) S\u1ed1 \u0111\u1ea1i \u0111\u1ed9i c\u00f3 l\u00e0:","15 : 3 = 5 (\u0111\u1ea1i \u0111\u1ed9i) C\u00e1ch 2: S\u1ed1 ti\u1ec3u \u0111\u1ed9i c\u00f3 l\u00e0: 900 : 15 = 60 (ti\u1ec3u \u0111\u1ed9i) S\u1ed1 ti\u1ec3u \u0111\u1ed9i gh\u00e9p th\u00e0nh 1 \u0111\u1ea1i \u0111\u1ed9i: 4 x 3 = 12 (ti\u1ec3u \u0111\u1ed9i) S\u1ed1 \u0111\u1ea1i \u0111\u1ed9i c\u00f3 l\u00e0: 60 : 12 = 5 (\u0111\u1ea1i \u0111\u1ed9i) \u0110\u00e1p s\u1ed1: 60 ti\u1ec3u \u0111\u1ed9i v\u00e0 5 \u0111\u1ea1i \u0111\u1ed9i. C\u00e2u 6: \u0110\u00e1p s\u1ed1: 11 xe taxi v\u00e0 6 xe lam. G\u1ee3i \u00fd: Gi\u1ea3 s\u1eed ta th\u00e1o b\u1edbt \u1edf m\u1ed7i xe taxi m\u1ed9t b\u00e1nh th\u00ec c\u1ea3 17 xe \u0111\u1ec1u c\u00f3 3 b\u00e1nh. C\u00e2u 7: \u0110\u00e1p s\u1ed1: Anh ta c\u00e2u \u0111\u01b0\u1ee3c 0 con c\u00e1. C\u00e2u 8: \u0110\u00e1p s\u1ed1: \u1ea4m n\u1eb7ng b\u1eb1ng 9 th\u1ecfi ch\u00ec. C\u00e2u 9: \u0110\u00e1p s\u1ed1: 34 v\u00e0 27","C\u00e1c s\u1ed1 lu\u00e2n phi\u00ean tr\u1eeb \u0111i 7 v\u00e0 c\u1ed9ng th\u00eam 4 \u0111\u01a1n v\u1ecb.","C\u00e2u 1: \u0110\u00e1p s\u1ed1: \u0110\u1ea7u n\u1eb7ng 450g, th\u00e2n n\u1eb7ng 600g, con c\u00e1 n\u1eb7ng 1.200g. C\u00e2u 2: \u0110\u00e1p s\u1ed1: 36, 27 C\u00e1c s\u1ed1 lu\u00e2n phi\u00ean nh\u00e2n 4 v\u00e0 tr\u1eeb \u0111i s\u1ed1 \u0111\u1ee9ng tr\u01b0\u1edbc. C\u00e2u 3: \u0110\u00e1p s\u1ed1: 15 xe taxi v\u00e0 6 xe lam. Gi\u1ea3 s\u1eed c\u00f3 19 xe taxi th\u00ec s\u1ed1 xe lam l\u00e0: 19 - 9 = 10 (xe lam) Hi\u1ec7u s\u1ed1 b\u00e1nh xe taxi v\u00e0 s\u1ed1 b\u00e1nh xe lam l\u00fac n\u00e0y l\u00e0: 19 x 4 - 10 x 3 = 46 (b\u00e1nh xe) N\u1ebfu ta b\u1edbt \u0111i m\u1ed9t xe taxi v\u00e0 m\u1ed9t xe lam th\u00ec hi\u1ec7u s\u1ed1 xe taxi v\u00e0 xe lam kh\u00f4ng thay \u0111\u1ed5i (v\u1eabn l\u00e0 9) nh\u01b0ng hi\u1ec7u s\u1ed1 b\u00e1nh xe s\u1ebd gi\u1ea3m \u0111i: 4 - 3 = 1 (b\u00e1nh xe) T\u1eeb 46 xu\u1ed1ng 42 th\u00ec ph\u1ea3i gi\u1ea3m b\u1edbt: 46 - 42 = 4 (b\u00e1nh xe) V\u1eady s\u1ed1 xe taxi (c\u0169ng l\u00e0 s\u1ed1 xe lam) ph\u1ea3i b\u1edbt \u0111i l\u00e0: 4 : 1 = 4 (xe)","Do \u0111\u00f3 s\u1ed1 xe taxi l\u00e0: 19 - 4 = 15 (xe) C\u00f2n s\u1ed1 xe lam l\u00e0: 10 - 4 = 6 (xe) C\u00e2u 4: \u0110\u00e1p s\u1ed1: 40 C\u00e1c s\u1ed1 \u0111\u00e3 cho h\u01a1n k\u00e9m nhau 5 \u0111\u01a1n v\u1ecb. C\u00e2u 5: \u0110\u00e1p s\u1ed1: N\u1ebfu b\u00e1n nh\u01b0 th\u1ebf th\u00ec l\u1ed7. C\u00e2u 6: T\u1ef1 gi\u1ea3i. C\u00e2u 7: \u0110\u00e1p s\u1ed1: 99 con tr\u00e2u 111 con ng\u1ef1a 198 con b\u00f2. G\u1ee3i \u00fd: Thay s\u1ed1 ng\u1ef1a b\u1eb1ng \\\"s\u1ed1 tr\u00e2u + 12\\\" v\u00e0 s\u1ed1 b\u00f2 b\u1eb1ng \\\"2 l\u1ea7n s\u1ed1 tr\u00e2u\\\" ta th\u1ea5y 408 ch\u00ednh l\u00e0: 4 l\u1ea7n s\u1ed1 tr\u00e2u + 12 con... C\u00e2u 8:","\u0110\u00e1p s\u1ed1: 119,2 S\u1ed1 sau l\u00e0 hai ch\u1eef s\u1ed1 cu\u1ed1i nh\u00e2n \u0111\u00f4i c\u1ee7a s\u1ed1 tr\u01b0\u1edbc. Do \u0111\u00f3: 96 x 2 = 192 Suy ra s\u1ed1 c\u1ea7n t\u00ecm l\u00e0 119,2 C\u00e2u 9: \u0110\u00e1p s\u1ed1: 90 s\u1ed1. C\u00e1c s\u1ed1 3 ch\u1eef s\u1ed1 m\u00e0 ch\u1eef s\u1ed1 h\u00e0ng \u0111\u01a1n v\u1ecb gi\u1ed1ng ch\u1eef s\u1ed1 h\u00e0ng tr\u0103m l\u00e0: 101, 111, 121, 131, 141, 151, 161, 171, 181, 191 (10 s\u1ed1). 202, 212, 222, 232, 242, 252, 262, 272, 282, 292 (10 s\u1ed1). 303, 313, 323, 333, 343, 353, 363, 373, 383, 393 (10 s\u1ed1). ...... 909, 919, 929, 939, 949, 959, 969, 979, 989, 999 (10 s\u1ed1). V\u1eady s\u1ed1 3 ch\u1eef s\u1ed1 m\u00e0 ch\u1eef s\u1ed1 h\u00e0ng \u0111\u01a1n v\u1ecb gi\u1ed1ng ch\u1eef s\u1ed1 h\u00e0ng tr\u0103m c\u00f3 t\u1ea5t c\u1ea3 l\u00e0: 10 x 9 = 90 (s\u1ed1) C\u00e2u 10: \u0110\u00e1p s\u1ed1: 22 g\u00e0 v\u00e0 14 ch\u00f3. C\u00e1ch 1: Gi\u1ea3 s\u1eed c\u00f3 8 con ch\u00f3 th\u00ec s\u1ed1 g\u00e0 s\u1ebd l\u00e0: 8 + 8 = 16 (con g\u00e0) T\u1ed5ng s\u1ed1 ch\u00e2n l\u00fac n\u00e0y s\u1ebd l\u00e0:","16 x 2 + 8 x 4 = 64 (ch\u00e2n) (*) \u0110\u1ec3 c\u00f3 \u0111\u1ee7 100 ch\u00e2n nh\u01b0 \u0111\u1ea7u b\u00e0i th\u00ec ph\u1ea3i t\u0103ng th\u00eam \u1edf t\u1ed5ng (*): 100 - 64 = 36 (ch\u00e2n) N\u1ebfu ta th\u00eam v\u00e0o 1 con ch\u00f3 v\u00e0 1 con g\u00e0 th\u00ec hi\u1ec7u s\u1ed1 g\u00e0 v\u00e0 s\u1ed1 ch\u00f3 kh\u00f4ng thay \u0111\u1ed5i (v\u1eabn l\u00e0 8) nh\u01b0ng t\u1ed5ng s\u1ed1 ch\u00e2n s\u1ebd t\u0103ng th\u00eam: 4 + 2 = 6 (ch\u00e2n) V\u1eady mu\u1ed1n t\u0103ng th\u00eam \u1edf t\u1ed5ng (*) 36 ch\u00e2n th\u00ec ph\u1ea3i t\u0103ng th\u00eam v\u00e0o s\u1ed1 g\u00e0 (ch\u00f3) l\u00e0: 36 : 6 = 6 (con) Do \u0111\u00f3 s\u1ed1 g\u00e0 l\u00e0: 16 + 6 = 22 (con) C\u00f2n s\u1ed1 ch\u00f3 l\u00e0: 22 - 8 = 14 (con) C\u00e1ch 2: N\u1ebfu b\u1edbt \u0111i 8 con g\u00e0 th\u00ec s\u1ed1 g\u00e0 s\u1ebd b\u1eb1ng s\u1ed1 ch\u00f3 v\u00e0 t\u1ed5ng s\u1ed1 ch\u00e2n ch\u1ec9 c\u00f2n l\u00e0: 100 - 8 x 2 = 84 (ch\u00e2n) V\u00ec s\u1ed1 ch\u00e2n m\u1ed7i con ch\u00f3 g\u1ea5p \u0111\u00f4i s\u1ed1 ch\u00e2n m\u1ed7i con g\u00e0 n\u00ean 84 ch\u00ednh l\u00e0 3 l\u1ea7n s\u1ed1 ch\u00e2n g\u00e0 (sau n\u00e0y). V\u1eady s\u1ed1 ch\u00e2n g\u00e0 sau n\u00e0y l\u00e0: 84 : 3 = 28 S\u1ed1 g\u00e0 sau n\u00e0y l\u00e0: 28 : 2 = 14 (con)","S\u1ed1 g\u00e0 l\u00fac \u0111\u1ea7u l\u00e0: 14 + 8 = 22 (con) S\u1ed1 ch\u00f3 l\u00e0: 22 - 8 = 14 (con)","B\u00e0i 39 C\u00e2u 1: \u0110\u00e1p s\u1ed1:14 Chia n\u1eeda h\u00ecnh tr\u00f2n \u0111\u01b0\u1eddng c\u1eaft gi\u1eefa 8 v\u00e0 11, 32 v\u00e0 3, ta c\u00f3 t\u1ed5ng c\u1ee7a c\u00e1c s\u1ed1 \u1edf m\u1ed7i n\u1eeda l\u00e0 54 32 + 8 + 9 + 5 = 54 11 + 14 + 26 + 3 = 54 C\u00e2u 2: \u0110\u00e1p s\u1ed1: \u0110\u00fang. C\u00e2u 3: \u0110\u00e1p s\u1ed1: \u0110\u1ed9i A: 22 b\u1ea1n \u0110\u1ed9i B: 14 b\u1ea1n \u0110\u1ed9i C: 12 b\u1ea1n. Sau 3 l\u1ea7n chuy\u1ec3n th\u00ec s\u1ed1 \u0111\u1ed9i vi\u00ean \u1edf ba \u0111\u1ed9i b\u1eb1ng nhau n\u00ean t\u1ed5ng s\u1ed1 \u0111\u1ed9i vi\u00ean ph\u1ea3i chia h\u1ebft cho 3. T\u1eeb 40 \u0111\u1ebfn 50 ch\u1ec9 c\u00f3 42, 45 v\u00e0 48 chi h\u1ebft cho 3 n\u00ean t\u1ed5ng s\u1ed1 \u0111\u1ed9i vi\u00ean ch\u1ec9 c\u00f3 42, 45 ho\u1eb7c 48. M\u1eb7t kh\u00e1c, sau l\u1ea7n chuy\u1ec3n th\u1ee9 ba th\u00ec s\u1ed1 \u0111\u1ed9i vi\u00ean c\u1ee7a \u0111\u1ed9i C ph\u1ea3i l\u00e0 s\u1ed1 ch\u1eb5n: B\u00e2y gi\u1edd ta x\u00e9t t\u1eebng tr\u01b0\u1eddng h\u1ee3p: a. N\u1ebfu t\u1ed5ng s\u1ed1 \u0111\u1ed9i vi\u00ean l\u00e0 42 th\u00ec sau l\u1ea7n chuy\u1ec3n th\u1ee9 ba m\u1ed7i \u0111\u1ed9i c\u00f3: 42 : 3 = 14 (b\u1ea1n)","Suy ra sau l\u1ea7n chuy\u1ec3n th\u1ee9 hai \u0111\u1ed9i A c\u00f3: 14 : 2 = 7 (b\u1ea1n) v\u00e0 \u0111\u1ed9i C c\u00f3: 14 + 7 = 21 (b\u1ea1n) kh\u00f4ng ph\u1ea3i l\u00e0 s\u1ed1 ch\u1eb5n. V\u1eady t\u1ed5ng s\u1ed1 \u0111\u1ed9i vi\u00ean kh\u00f4ng th\u1ec3 l\u00e0 42. b. N\u1ebfu t\u1ed5ng s\u1ed1 \u0111\u1ed9i vi\u00ean l\u00e0 45 th\u00ec sau l\u1ea7n chuy\u1ec3n th\u1ee9 ba \u0111\u1ed9i A c\u00f3: 45 : 3 = 15 (b\u1ea1n) kh\u00f4ng ph\u1ea3i l\u00e0 s\u1ed1 ch\u1eb5n. V\u1eady t\u1ed5ng s\u1ed1 \u0111\u1ed9i vi\u00ean kh\u00f4ng th\u1ec3 l\u00e0 45 c. N\u1ebfu t\u1ed5ng s\u1ed1 \u0111\u1ed9i vi\u00ean l\u00e0 48 th\u00ec sau l\u1ea7n chuy\u1ec3n th\u1ee9 ba m\u1ed7i \u0111\u1ed9i c\u00f3: 48 : 3 = 16 (b\u1ea1n) V\u1eady sau l\u1ea7n chuy\u1ec3n th\u1ee9 nh\u1ea5t \u0111\u1ed9i C c\u00f3: 4 : 2 = 2 (b\u1ea1n) c\u00f2n \u0111\u1ed9i B c\u00f3: 16 + 12 = 28 (b\u1ea1n) Do \u0111\u00f3 l\u00fac \u0111\u1ea7u: \u0110\u1ed9i B c\u00f3: 28 : 2 = 14 (b\u1ea1n) \u0110\u1ed9i A c\u00f3: 14 + 8 = 22 (b\u1ea1n) \u0110\u1ed9i C c\u00f3: 12 b\u1ea1n. C\u00e2u 4: \u0110\u00e1p s\u1ed1: 360 ph\u00fat. 1 ng\u00e0y c\u00f3 24 gi\u1edd.","S\u1ed1 gi\u1edd c\u1ee7a c\u1ee7a m\u1ed9t ph\u1ea7n t\u01b0 ng\u00e0y l\u00e0: 24 : 4 = 6 (gi\u1edd) S\u1ed1 ph\u00fat c\u1ee7a m\u1ed9t ph\u1ea7n t\u01b0 ng\u00e0y l\u00e0: 60 x 6 = 360 (ph\u00fat) C\u00e2u 5: \u0110\u00e1p s\u1ed1: 7 C\u00e1c ch\u1eef s\u1ed1 h\u00e0ng d\u1ecdc c\u1ed9ng l\u1ea1i th\u00e0nh 21 C\u00e2u 6: T\u1ef1 gi\u1ea3i. C\u00e2u 7: \u0110\u00e1p s\u1ed1: 4 v\u00e0 5 V\u00ec 20 = 1 x 20 = 2 x 10 = 4 x 5 n\u00ean hai s\u1ed1 \u0111\u00f3 c\u00f3 th\u1ec3 l\u00e0: 1 v\u00e0 20, 2 v\u00e0 10, 4 v\u00e0 5 Th\u1eed t\u1eebng tr\u01b0\u1eddng h\u1ee3p: a. 1 + 20 = 21 kh\u00e1c 9 (lo\u1ea1i) b. 2 + 10 = 12 kh\u00e1c 9 (lo\u1ea1i) c. 4 + 5 = 9 b\u1eb1ng 9 (ch\u1ecdn) V\u1eady hai s\u1ed1 \u0111\u00f3 l\u00e0 4 v\u00e0 5 C\u00e2u 8: C\u00e1c s\u1ed1 c\u00f3 2 ch\u1eef s\u1ed1 c\u00f3 h\u00e0ng ch\u1ee5c l\u1edbn h\u01a1n h\u00e0ng \u0111\u01a1n v\u1ecb l\u00e0:"]