{"id":25642,"date":"2021-12-24T17:36:42","date_gmt":"2021-12-24T10:36:42","guid":{"rendered":"https:\/\/www.vietlearn.org\/post\/?p=25642"},"modified":"2021-12-24T17:36:43","modified_gmt":"2021-12-24T10:36:43","slug":"bai-so-39-do-vui-luyen-tri-thong-minh","status":"publish","type":"post","link":"https:\/\/www.vietlearn.org\/kien-thuc\/bai-so-39-do-vui-luyen-tri-thong-minh\/","title":{"rendered":"B\u00c0I S\u1ed0 39 – \u0110\u1ed1 vui luy\u1ec7n tr\u00ed th\u00f4ng minh"},"content":{"rendered":"

<\/a>C\u00c2U 1:<\/h3>\n

S\u1ed1 n\u00e0o thay cho d\u1ea5u ch\u1ea5m h\u1ecfi<\/p>\n\n\n\n\n\n\n\n\n
A<\/td>\nB<\/td>\nC<\/td>\nD<\/td>\n<\/tr>\n
2<\/td>\n3<\/td>\n5<\/td>\n7<\/td>\n<\/tr>\n
—<\/td>\n—<\/td>\n—<\/td>\n—<\/td>\n<\/tr>\n
7<\/td>\n8<\/td>\n9<\/td>\n10<\/td>\n<\/tr>\n
16<\/td>\n17<\/td>\n17<\/td>\n18<\/td>\n<\/tr>\n
?<\/td>\n?<\/td>\n?<\/td>\n?<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

<\/a>C\u00c2U 2:<\/h3>\n

Ti\u1ebfp theo tr\u00ecnh t\u1ef1 s\u1ebd l\u00e0 h\u00ecnh n\u00e0o?<\/p>\n

\"84.jpg\"<\/p>\n

<\/a>C\u00c2U 3:<\/h3>\n

Hai b\u1ea1n Th\u0103ng v\u00e0 Long c\u00f9ng ch\u01a1i tr\u00f2 ch\u01a1i: tr\u00ean m\u1eb7t b\u00e0n c\u00f3 3 c\u00e1i h\u1ed9p, h\u1ed9p th\u1ee9 nh\u1ea5t \u0111\u1ef1ng 20 vi\u00ean bi, h\u1ed9p th\u1ee9 hai \u0111\u1ef1ng 25 vi\u00ean bi, h\u1ed9p th\u1ee9 ba \u0111\u1ef1ng 20 vi\u00ean bi. M\u1ed7i l\u1ea7n \u0111\u1ebfn l\u01b0\u1ee3t m\u00ecnh, m\u1ed7i ng\u01b0\u1eddi \u0111\u01b0\u1ee3c l\u1ea5y \u0111i s\u1ed1 vi\u00ean bi t\u00f9y \u00fd trong c\u00f9ng m\u1ed9t h\u1ed9p, ai l\u1ea5y \u0111\u01b0\u1ee3c vi\u00ean bi cu\u1ed1i c\u00f9ng l\u00e0 ng\u01b0\u1eddi th\u1eafng cu\u1ed9c. Th\u0103ng \u0111\u01b0\u1ee3c gh\u00e9p \u0111i tr\u01b0\u1edbc. H\u00e3y gi\u00fap th\u0103ng b\u00ed quy\u1ebft \u0111\u1ec3 Th\u0103ng ch\u1eafc ch\u1eafn th\u1eafng trong cu\u1ed9c thi n\u00e0y nh\u00e9!<\/p>\n

<\/a>C\u00c2U 4:<\/h3>\n

M\u1ed9t ng\u01b0\u1eddi h\u1ecfi \u00f4ng l\u00e3o \u0111ang c\u00e2u c\u00e1 l\u00e0 c\u00e2u \u0111\u01b0\u1ee3c m\u1ea5y con r\u1ed3i? \u00f4ng l\u00e3o tr\u1ea3 l\u1eddi: “s\u00e1u con kh\u00f4ng \u0111\u1ea7u, ch\u00edn con kh\u00f4ng \u0111u\u00f4i, t\u00e1m con b\u1ecb \u0111\u1ee9t ngang th\u00e2n”. H\u1ecfi \u00f4ng l\u00e3o c\u00e2u \u0111\u01b0\u1ee3c m\u1ea5y con c\u00e1?<\/p>\n

<\/a>C\u00c2U 5:<\/h3>\n

a<\/p>\n

b c<\/p>\n

d e f<\/p>\n

g h<\/p>\n

i<\/p>\n

B\u1ea1n h\u00e3y thay nh\u1eefng ch\u1eef c\u00e1i t\u1eeb a \u0111\u1ebfn i b\u1eb1ng nh\u1eefng con s\u1ed1 t\u1eeb 10 \u0111\u1ebfn 99 sao cho:<\/p>\n

– Ch\u00fang l\u00e0 9 s\u1ed1 li\u1ec1n nhau (v\u00ed d\u1ee5 10 \u0111\u1ebfn 18)<\/p>\n

– C\u00f3 3 s\u1ed1 trong ch\u00fang l\u00e0 s\u1ed1 nguy\u00ean t\u1ed1 (s\u1ed1 nguy\u00ean t\u1ed1 ch\u1ec9 chia \u0111\u01b0\u1ee3c cho 1 v\u00e0 ch\u00ednh n\u00f3 nh\u01b0 11, 13, 17, 19, 23…)<\/p>\n

– T\u1ed5ng c\u1ee7a t\u1ea5t c\u1ea3 c\u00e1c con s\u1ed1 c\u1ee7a ch\u00fang nh\u1ecf h\u01a1n 60 (v\u00ed d\u1ee5 n\u1ebfu a \u0111\u1ebfn i l\u00e0 10 \u0111\u1ebfn 18 th\u00ec b\u1ea1n c\u1ed9ng nh\u01b0 sau: 1+ 0 + 1+ 1+ 1+ 2+ 1+ 3+ 1 + 4 + 1 + 5 + 1+ 6… > 60).<\/p>\n

– T\u1ed5ng c\u1ee7a t\u1eebng h\u00e0ng ngang \u0111\u1ec1u l\u00e0 s\u1ed1 nguy\u00ean t\u1ed1<\/p>\n

<\/a>C\u00c2U 6:<\/h3>\n

Minh, H\u00e0 v\u00e0 Tu\u1ea5n \u1edf chung m\u1ed9t c\u0103n nh\u00e0 tranh. \u0110\u00e2y l\u00e0 1 c\u0103n nh\u00e0 c\u0169 c\u00f3 m\u1ed9t chi\u1ebfc b\u1ebfp n\u1ea5u. Minh \u0111\u1eb7t 3 kh\u00fac c\u1ee7i v\u00e0o b\u1ebfp, H\u00e0 th\u00eam v\u00e0o 5 kh\u00fac, c\u00f2n Tu\u1ea5n kh\u00f4ng c\u00f3 kh\u00fac c\u1ee7i n\u00e0o, b\u00e8n tr\u1ea3 ti\u1ec1n cho Minh, H\u00e0 8 \u0111\u1ed3ng \u0111\u1ec3 \u0111\u00f3ng g\u00f3p. V\u1eady Minh v\u00e0 H\u00e0 s\u1ebd chia nhau s\u1ed1 ti\u1ec1n \u1ea5y nh\u01b0 th\u1ebf n\u00e0o?<\/p>\n

<\/a>C\u00c2U 7:<\/h3>\n

C\u00f3 1 qu\u1ea3 d\u01b0a h\u1ea5u b\u1ea1n l\u00e0m sao ch\u1ec9 c\u1ea7n 3 nh\u00e1t dao (\u0111\u01b0\u1eddng th\u1eb3ng) chia tr\u00e1i d\u01b0a h\u1ea5u ra 8 mi\u1ebfng?<\/p>\n

H\u01af\u1edaNG D\u1eaaN – B\u00c0I GI\u1ea2I – \u0110\u00c1P S\u1ed0<\/h1>\n

<\/a>B\u00c0I S\u1ed0 39<\/h2>\n

<\/a>C\u00c2U 1:<\/h3>\n

Th\u1ee9 t\u1ef1 c\u00e1c s\u1ed1 \u0111i\u1ec1n v\u00e0o d\u1ea5u ch\u1ea5m h\u1ecfi s\u1ebd l\u00e0:<\/p>\n

33, 34, 34, 35<\/p>\n

Ta c\u00f3:<\/p>\n

A + C = A => 2 + 5 = 7<\/p>\n

B + C = B => 3+ 5 = 8<\/p>\n

A + D = C => 2 + 7 = 9<\/p>\n

B + D = D => 3 + 7 = 10<\/p>\n

L\u00e0m t\u01b0\u01a1ng t\u1ef1 nh\u01b0 v\u1eady ta \u0111\u01b0\u1ee3c k\u1ebft qu\u1ea3: 33, 34, 34, 35<\/p>\n

<\/a>C\u00c2U 2:<\/h3>\n

\u0110\u00e1p \u00e1n: E<\/p>\n

Hai c\u1ea1nh xu\u1ea5t ph\u00e1t t\u1eeb v\u1ecb tr\u00ed th\u1eb3ng \u0111\u1ee9ng, d\u1ecbch chuy\u1ec3n theo chi\u1ec1u kim \u0111\u1ed3ng h\u1ed3 v\u00e0 ng\u01b0\u1ee3c chi\u1ec1u kim \u0111\u1ed3ng h\u1ed3 \u1edf m\u1ed7i giai \u0111o\u1ea1n.<\/p>\n

<\/a>C\u00c2U 3:<\/h3>\n

\u0110\u1ec3 l\u1ea5y \u0111\u01b0\u1ee3c vi\u00ean bi cu\u1ed1i c\u00f9ng, th\u00ec khi Th\u0103ng \u0111\u01b0\u1ee3c ph\u00e9p \u0111i tr\u01b0\u1edbc, Th\u0103ng h\u00e3y l\u1ea5y l\u1ea7n \u0111\u1ea7u 25 vi\u00ean \u1edf h\u1ed9p bi th\u1ee9 2. Sau \u0111\u00f3 n\u1ebfu Long l\u1ea5y bao nhi\u00eau vi\u00ean bi \u1edf m\u1ed9t h\u1ed9p th\u00ec Th\u0103ng c\u0169ng l\u1ea5y b\u1ea5y nhi\u00eau vi\u00ean bi \u1edf h\u1ed9p bi kia (kh\u00f4ng l\u1ea5y bi c\u00f9ng h\u1ed9p m\u00e0 Long \u0111\u00e3 l\u1ea5y). C\u1ee9 nh\u01b0 th\u1ebf, ch\u1eafc ch\u1eafn Th\u0103ng s\u1ebd l\u00e0 ng\u01b0\u1eddi l\u1ea5y nh\u1eefng vi\u00ean bi cu\u1ed1i c\u00f9ng.<\/p>\n

<\/a>C\u00c2U 4:<\/h3>\n

\u0110\u00e1p s\u1ed1: 0 con.<\/p>\n

<\/a>C\u00c2U 5:<\/h3>\n

C\u00e1ch 1:<\/p>\n

a——–13<\/p>\n

b c——14 15<\/p>\n

d e f—-16 19 1<\/p>\n

g h——20 21<\/p>\n

i———17<\/p>\n

C\u00e1ch 2:<\/p>\n

17<\/p>\n

22 25<\/p>\n

18 20 21<\/p>\n

23 24<\/p>\n

19<\/p>\n

<\/a>C\u00c2U 6:<\/h3>\n

Tu\u1ea5n ph\u1ea3i \u0111\u00f3ng 8 (\u0111) <=> s\u1ed1 c\u1ee7i c\u1ea7n \u0111\u00f3ng g\u00f3p<\/p>\n

=> Minh = H\u00e0 = Tu\u1ea5n = 8 (\u0111)<\/p>\n

Ta c\u00f3 t\u1ed5ng s\u1ed1 ti\u1ec1n l\u00e0 8 x 3 = 24 (\u0111)<\/p>\n

v\u00e0 t\u1ed5ng s\u1ed1 c\u1ee7i hi\u1ec7n c\u00f3 l\u00e0 8 kh\u00fac c\u1ee7i => 1 kh\u00fac c\u1ee7i <=> 3 (\u0111). T\u1eeb \u0111\u00f3 d\u1ec5 nh\u1eadn th\u1ea5y Minh \u0111\u00e3 \u0111\u00f3ng v\u00e0o 3 x 3 = 9 (\u0111) => s\u1ed1 ti\u1ec1n c\u1ea7n l\u1ea5y l\u1ea1i.<\/p>\n

9 – 8= 1 (\u0111)<\/p>\n

v\u00e0 H\u00e0 l\u00e0 3 x 5 = 15 \u0111 => s\u1ed1 ti\u1ec1n c\u1ea7n l\u1ea5y l\u1ea1i<\/p>\n

15 – 8 = 7 (\u0111).<\/p>\n

Suy ra Tu\u1ea5n ph\u1ea3i tr\u1ea3 cho minh 1\u0111, tr\u1ea3 cho H\u00e0 7\u0111.<\/p>\n

<\/a>C\u00c2U 7:<\/h3>\n

Nh\u00e1t th\u1ee9 nh\u1ea5t b\u1ed5 d\u1ecdc chia qu\u1ea3 d\u01b0a l\u00e0m 2. G\u1ed9p 2 n\u1eeda d\u01b0a l\u1ea1i b\u1ed5 d\u1ecdc nh\u00e1t th\u1ee9 2. Nh\u00e1t th\u1ee9 3 b\u1ed5 ngang gi\u1eefa b\u1ee5ng qu\u1ea3 d\u01b0a. Nh\u01b0 v\u1eady ta s\u1ebd \u0111\u01b0\u1ee3c 8 mi\u1ebfng d\u01b0a.<\/p>\n","protected":false},"excerpt":{"rendered":"

C\u00c2U 1: S\u1ed1 n\u00e0o thay cho d\u1ea5u ch\u1ea5m h\u1ecfi A B C D 2 3 5 7 — — — — 7 8 9 10 16 17 17 18 ? ? ? ? C\u00c2U 2: Ti\u1ebfp theo tr\u00ecnh t\u1ef1 s\u1ebd l\u00e0 h\u00ecnh n\u00e0o? C\u00c2U 3: Hai b\u1ea1n Th\u0103ng v\u00e0 Long c\u00f9ng ch\u01a1i tr\u00f2 ch\u01a1i: tr\u00ean […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_disable_autopaging":false},"categories":[47],"tags":[],"class_list":["post-25642","post","type-post","status-publish","format-standard","hentry","category-do-vui"],"_links":{"self":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/25642","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/comments?post=25642"}],"version-history":[{"count":1,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/25642\/revisions"}],"predecessor-version":[{"id":25644,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/25642\/revisions\/25644"}],"wp:attachment":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/media?parent=25642"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/categories?post=25642"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/tags?post=25642"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}