{"id":25574,"date":"2021-12-24T17:22:34","date_gmt":"2021-12-24T10:22:34","guid":{"rendered":"https:\/\/www.vietlearn.org\/post\/?p=25574"},"modified":"2021-12-24T17:22:34","modified_gmt":"2021-12-24T10:22:34","slug":"bai-so-27-do-vui-luyen-tri-thong-minh","status":"publish","type":"post","link":"https:\/\/www.vietlearn.org\/kien-thuc\/bai-so-27-do-vui-luyen-tri-thong-minh\/","title":{"rendered":"B\u00c0I S\u1ed0 27 – \u0110\u1ed1 vui luy\u1ec7n tr\u00ed th\u00f4ng minh"},"content":{"rendered":"

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

\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o d\u1ea5u ch\u1ea5m h\u1ecfi (?).<\/p>\n

\"53.jpg\"<\/p>\n

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

Ch\u1ecdn h\u00ecnh kh\u00e1c nh\u1ea5t trong c\u00e1c h\u00ecnh A, B, C, D, E:<\/p>\n

\"54.jpg\"<\/p>\n

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

Nh\u1eefng \u0111i\u1ec1u ly k\u00ec v\u1ec1 hai c\u00f4 lan truy\u1ec1n \u0111i kh\u1eafp n\u01a1i. C\u00f4 Nh\u1ea5t kh\u00f4ng c\u00f3 kh\u1ea3 n\u0103ng n\u00f3i \u0111\u00fang v\u00e0o nh\u1eefng ng\u00e0y th\u1ee9 hai, th\u1ee9 ba, th\u1ee9 t\u01b0, c\u00f2n nh\u1eefng ng\u00e0y kh\u00e1c n\u00f3i \u0111\u00fang. C\u00f4 Nh\u1ecb n\u00f3i sai v\u00e0o nh\u1eefng ng\u00e0y th\u1ee9 ba, n\u0103m v\u00e0 th\u1ee9 b\u1ea3y, c\u00f2n nh\u1eefng ng\u00e0y kh\u00e1c n\u00f3i \u0111\u00fang.<\/p>\n

M\u1ed9t l\u1ea7n t\u00f4i g\u1eb7p hai c\u00f4 v\u00e0 h\u1ecfi m\u1ed9t trong hai ng\u01b0\u1eddi:<\/p>\n

– C\u00f4 h\u00e3y cho bi\u1ebft, c\u00f4 l\u00e0 ai?<\/p>\n

– T\u00f4i l\u00e0 Nh\u1ea5t<\/p>\n

– C\u00f4 h\u00e3y n\u00f3i th\u00eam h\u00f4m nay l\u00e0 th\u1ee9 m\u1ea5y?<\/p>\n

– H\u00f4m nay l\u00e0 ch\u1ee7 nh\u1eadt .<\/p>\n

C\u00f4 kia b\u1ed7ng n\u00f3i xen v\u00e0o:<\/p>\n

– Ng\u00e0y mai l\u00e0 th\u1ee9 s\u00e1u .<\/p>\n

T\u00f4i s\u1eefng s\u1edd ng\u1ea1c nhi\u00ean – Sao l\u1ea1i th\u1ebf \u0111\u01b0\u1ee3c? v\u00e0 quay sang h\u1ecfi c\u00f4 \u0111\u00f3:<\/p>\n

– C\u00f4 cam \u0111oan l\u00e0 c\u00f4 n\u00f3i th\u1eadt ch\u1ee9?<\/p>\n

– Ng\u00e0y th\u1ee9 t\u01b0 t\u00f4i lu\u00f4n n\u00f3i th\u1eadt \u2013 c\u00f4 \u0111\u00f3 tr\u1ea3 l\u1eddi.<\/p>\n

Hai c\u00f4 l\u00e0m t\u00f4i l\u00fang t\u00fang th\u1eadt s\u1ef1, nh\u01b0ng sau m\u1ed9t h\u1ed3i suy ngh\u0129 t\u00f4i \u0111\u00e3 x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c c\u00f4 n\u00e0o l\u00e0 c\u00f4 Nh\u1ea5t, c\u00f4 n\u00e0o l\u00e0 c\u00f4 Nh\u1ecb, th\u1eadm ch\u00ed c\u00f2n x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c ng\u00e0y h\u00f4m \u0111\u00f3 l\u00e0 th\u1ee9 m\u1ea5y.<\/p>\n

C\u00e1c b\u1ea1n h\u00e3y \u0111o\u00e1n th\u1eed xem.<\/p>\n

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

30 chia 1\/2, v\u00e0 c\u1ed9ng th\u00eam 10, b\u1eb1ng bao nhi\u00eau?<\/p>\n

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

T\u1eeb 1 \u0111i\u1ec3m xu\u1ea5t ph\u00e1t ban \u0111\u1ea7u, b\u1ea1n ti\u1ebfn theo 1 \u0111\u01b0\u1eddng th\u1eb3ng sau \u0111\u00f3 quay 1 g\u00f3c 90o v\u00e0 ti\u1ebfp t\u1ee5c \u0111i th\u1eb3ng (theo g\u00f3c 90o ban n\u00e3y b\u1ea1n v\u1eeba t\u1ea1o ra) \u0111\u01b0\u1ee3c 1 \u0111o\u1ea1n \u0111\u01b0\u1eddng b\u1ea5t k\u1ef3 b\u1ea1n l\u1ea1i quay ng\u01b0\u1eddi (\u0111\u1ed5i h\u01b0\u1edbng \u0111i) 1 g\u00f3c 90o v\u00e0 \u0111i ti\u1ebfp \u0111\u1ec3 tr\u1edf v\u1ec1 v\u1ecb tr\u00ed ban \u0111\u1ea7u. Nh\u01b0 v\u1eady ch\u1ec9 v\u1edbi 2 l\u1ea7n quay 1 g\u00f3c 90o b\u1ea1n ph\u1ea3i quay v\u1ec1 v\u1ecb tr\u00ed xu\u1ea5t ph\u00e1t (l\u01b0u \u00fd: b\u1ea1n kh\u00f4ng \u0111\u01b0\u1ee3c \u0111\u1ee9ng nguy\u00ean 1 ch\u1ed7 ban \u0111\u1ea7u – hay quay li\u00ean ti\u1ebfp 90o t\u1ea1i 1 \u0111i\u1ec3m) m\u00e0 ph\u1ea3i quay 2 l\u1ea7n 90o \u1edf 2 \u0111i\u1ec3m kh\u00e1c nhau. B\u1ea1n n\u00e0o c\u00f3 th\u1ec3 th\u1ef1c hi\u1ec7n \u0111\u01b0\u1ee3c \u0111i\u1ec1u n\u00e0y.<\/p>\n

G\u1ee3i \u00fd: kh\u00f4ng n\u00ean suy lu\u1eadn theo ph\u01b0\u01a1ng ph\u00e1p to\u00e1n h\u1ecdc th\u00f4ng th\u01b0\u1eddng.<\/p>\n

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

<\/a>B\u00c0I S\u1ed0 27<\/h2>\n

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

\"153.jpg\"<\/p>\n

Hai h\u00ecnh t\u00e1ch nhau ta \u0111em c\u1ed9ng v\u00e0o nhau. Hai h\u00ecnh giao nhau ta \u0111em nh\u00e2n v\u1edbi nhau.<\/p>\n

D\u1ef1a v\u00e0o s\u1ed1 c\u1ee7a c\u00e1c h\u00ecnh ta c\u00f3 th\u1ec3 suy lu\u1eadn: h\u00ecnh tr\u00f2n b\u1eb1ng 2, h\u00ecnh vu\u00f4ng b\u1eb1ng 3.<\/p>\n

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

H\u00ecnh th\u1ee9 nh\u1ea5t: 2 + 3 + 3 = 8<\/p>\n

H\u00ecnh th\u1ee9 hai: 2 + 2 + 3 = 7<\/p>\n

H\u00ecnh th\u1ee9 ba: 2 x 3 = 6<\/p>\n

V\u1eady h\u00ecnh cu\u1ed1i c\u00f9ng: 2 x 2 + 3 x 3 = 13<\/p>\n

S\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o d\u1ea5u ch\u1ea5m h\u1ecfi l\u00e0 13.<\/p>\n

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

H\u00ecnh b\u1ecb lo\u1ea1i l\u00e0 h\u00ecnh B<\/p>\n

Ta nh\u1eadn th\u1ea5y \u1edf c\u00e1c h\u00ecnh A, C, D, E th\u00ec c\u00e1c h\u00ecnh \u1edf n\u1eeda ph\u1ea7n tr\u00ean t\u00e1ch r\u1eddi nhau. C\u00e1c h\u00ecnh \u1edf n\u1eeda ph\u1ea7n d\u01b0\u1edbi giao nhau. Ri\u00eang h\u00ecnh B, hai h\u00ecnh \u1edf n\u1eeda ph\u1ea7n d\u01b0\u1edbi ch\u1ec9 m\u1edbi ch\u1ea1m v\u00e0o nhau. K\u1ebft qu\u1ea3 h\u00ecnh B b\u1ecb lo\u1ea1i.<\/p>\n

\"154.jpg\"<\/p>\n

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

B\u00e0i gi\u1ea3i:<\/p>\n

Gi\u1ea3 s\u1eed c\u00f4 tr\u1ea3 l\u1eddi \u0111\u1ea7u ti\u00ean l\u00e0 c\u00f4 A, c\u00f4 c\u00f2n l\u1ea1i l\u00e0 c\u00f4 B.<\/p>\n

+ V\u00ec ta th\u1ea5y c\u00e2u tr\u1ea3 l\u1eddi c\u1ee7a 2 ng\u01b0\u1eddi A v\u00e0 B m\u00e2u thu\u1eabn nhau (h\u00f4m nay l\u00e0 ch\u1ee7 nh\u1eadt, ng\u00e0y mai l\u00e0 th\u1ee9 s\u00e1u) n\u00ean \u0111\u00f3 s\u1ebd kh\u00f4ng ph\u1ea3i l\u00e0: th\u1ee9 s\u00e1u v\u00e0 ch\u1ee7 nh\u1eadt (ng\u00e0y m\u00e0 c\u1ea3 2 ng\u01b0\u1eddi c\u0169ng n\u00f3i th\u1eadt). Do \u0111\u00f3, c\u00f4 A l\u00e0 ng\u01b0\u1eddi n\u00f3i sai.<\/p>\n

+ N\u1ebfu c\u00f4 B n\u00f3i \u0111\u00fang th\u00ec h\u00f4m nay l\u00e0 th\u1ee9 5, n\u00ean B = c\u00f4 Nh\u1ecb (th\u1ee9 5 ch\u1ec9 c\u00f3 c\u00f4 Nh\u1ecb n\u00f3i \u0111\u00fang); nh\u01b0ng nh\u01b0 th\u1ebf l\u1ea1i v\u00f4 l\u00fd v\u00ec: th\u1ee9 4 c\u00f4 Nh\u1ecb kh\u00f4ng n\u00f3i th\u1eadt. Do \u0111\u00f3, c\u00f4 B c\u0169ng l\u00e0 ng\u01b0\u1eddi n\u00f3i sai.<\/p>\n

Nh\u01b0 v\u1eady h\u00f4m \u0111\u00f3 ng\u00e0y th\u1ee9 3, ng\u00e0y m\u00e0 c\u1ea3 hai ng\u01b0\u1eddi \u0111\u1ec1u n\u00f3i sai.<\/p>\n

Do \u0111\u00f3, c\u00f4 A l\u00e0 c\u00f4 Nh\u1ecb, c\u00f4 B l\u00e0 c\u00f4 Nh\u1ea5t<\/p>\n

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

\u0110\u00e1p s\u1ed1: 70<\/p>\n

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

B\u00e0i gi\u1ea3i:<\/p>\n

K\u00ed hi\u1ec7u (\u2022) l\u00e0 \u0111i\u1ec3m xu\u1ea5t ph\u00e1t. \u0110i theo h\u01b0\u1edbng chi\u1ec1u m\u0169i t\u00ean.<\/p>\n

\"155.jpg\"<\/p>\n","protected":false},"excerpt":{"rendered":"

C\u00c2U 1: \u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o d\u1ea5u ch\u1ea5m h\u1ecfi (?). C\u00c2U 2: Ch\u1ecdn h\u00ecnh kh\u00e1c nh\u1ea5t trong c\u00e1c h\u00ecnh A, B, C, D, E: C\u00c2U 3: Nh\u1eefng \u0111i\u1ec1u ly k\u00ec v\u1ec1 hai c\u00f4 lan truy\u1ec1n \u0111i kh\u1eafp n\u01a1i. C\u00f4 Nh\u1ea5t kh\u00f4ng c\u00f3 kh\u1ea3 n\u0103ng n\u00f3i \u0111\u00fang v\u00e0o nh\u1eefng ng\u00e0y th\u1ee9 hai, th\u1ee9 ba, th\u1ee9 […]<\/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-25574","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\/25574","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=25574"}],"version-history":[{"count":1,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/25574\/revisions"}],"predecessor-version":[{"id":25581,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/25574\/revisions\/25581"}],"wp:attachment":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/media?parent=25574"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/categories?post=25574"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/tags?post=25574"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}