{"id":25454,"date":"2021-12-24T16:48:54","date_gmt":"2021-12-24T09:48:54","guid":{"rendered":"https:\/\/www.vietlearn.org\/post\/?p=25454"},"modified":"2021-12-24T16:48:54","modified_gmt":"2021-12-24T09:48:54","slug":"bai-so-4-do-vui-luyen-tri-thong-minh","status":"publish","type":"post","link":"https:\/\/www.vietlearn.org\/kien-thuc\/bai-so-4-do-vui-luyen-tri-thong-minh\/","title":{"rendered":"B\u00c0I S\u1ed0 4 – \u0110\u1ed1 vui luy\u1ec7n tr\u00ed th\u00f4ng minh"},"content":{"rendered":"

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

Nh\u00ecn h\u00ecnh \u0111i\u1ec1n s\u1ed1?<\/p>\n

\"10_1.jpg\"<\/p>\n

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

B\u1ea1n \u0111o\u00e1n xem s\u1ed1 n\u00e0o nh\u00e9?<\/p>\n

\"10_2.jpg\"<\/p>\n

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

B\u1ea1n h\u00e3y di chuy\u1ec3n hai que di\u00eam l\u1ea1i \u0111\u00fang v\u1ecb tr\u00ed \u0111\u1ec3 k\u1ebft qu\u1ea3 ph\u00e9p T\u00ednh l\u00e0 \u0111\u00fang:<\/p>\n

\"11.jpg\"<\/p>\n

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

S\u1ed1 n\u00e0y n\u1eb1m trong ph\u1ea1m vi c\u00e1c s\u1ed1 t\u1ef1 nhi\u00ean t\u1eeb 1 \u0111\u1ebfn 58. Khi vi\u1ebft “n\u00f3” kh\u00f4ng s\u1eed d\u1ee5ng c\u00e1c ch\u1eef s\u1ed1<\/p>\n

1; 2; 3.<\/p>\n

Ngo\u00e0i ra “n\u00f3” l\u00e0 s\u1ed1 l\u1ebb v\u00e0 kh\u00f4ng chia h\u1ebft cho c\u00e1c s\u1ed1 3; 5; 7. V\u1eady “n\u00f3” l\u00e0 s\u1ed1 n\u00e0o?<\/p>\n

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

(\u0110\u1ed1 m\u1eb9o):<\/p>\n

N\u1ebfu ch\u1ec9 c\u00f3 m\u1ed9t que di\u00eam, trong m\u1ed9t ng\u00e0y m\u00f9a \u0111\u00f4ng gi\u00e1 r\u00e9t, b\u1ea1n b\u01b0\u1edbc v\u00e0o c\u0103n ph\u00f2ng c\u00f3 m\u1ed9t c\u00e2y \u0111\u00e8n, m\u1ed9t b\u1ebfp d\u1ea7u v\u00e0 m\u1ed9t b\u1ebfp c\u1ee7i, b\u1ea1n s\u1ebd th\u1eafp v\u00e0o \u0111\u00e2u tr\u01b0\u1edbc ti\u00ean?<\/p>\n

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

Ba ho\u00e0ng t\u1eed \u1edf ba n\u01b0\u1edbc l\u00e0ng gi\u1ec1ng mu\u1ed1n c\u1ea7u h\u00f4n v\u1edbi c\u00f4ng ch\u00faa. Vua cha \u0111\u1eb7t ra c\u00e2u h\u1ecfi sau:<\/p>\n

\u201cGi\u1ecf n\u00e0y \u0111\u1ef1ng m\u1eadn. N\u1ebfu ta cho ho\u00e0ng t\u1eed th\u1ee9 nh\u1ea5t m\u1ed9t n\u1eeda s\u1ed1 m\u1eadn v\u00e0 th\u00eam m\u1ed9t qu\u1ea3, ho\u00e0ng t\u1eed th\u1ee9 hai m\u1ed9t n\u1eeda s\u1ed1 m\u1eadn c\u00f2n l\u1ea1i v\u00e0 th\u00eam hai qu\u1ea3. Ho\u00e0ng t\u1eed th\u1ee9 ba m\u1ed9t n\u1eeda s\u1ed1 m\u1eadn c\u00f2n l\u1ea1i v\u00e0 th\u00eam 3 qu\u1ea3, th\u00ec gi\u1ecf m\u1eadn s\u1ebd kh\u00f4ng c\u00f2n qu\u1ea3 n\u00e0o\u201d.<\/p>\n

N\u1ebfu ai t\u00ecm \u0111\u01b0\u1ee3c l\u00fac \u0111\u1ea7u trong gi\u1ecf c\u00f3 bao nhi\u00eau qu\u1ea3 m\u1eadn th\u00ec s\u1ebd \u0111\u01b0\u1ee3c c\u01b0\u1edbi c\u00f4ng ch\u00faa. M\u1ea5y ch\u00e0ng ho\u00e0ng t\u1eed n\u1ecd ngh\u0129 m\u00e3i kh\u00f4ng ra, b\u1ea1n h\u00e3y th\u1eed gi\u1ea3i gi\u00fap h\u1ecd?<\/p>\n

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

<\/a>B\u00c0I S\u1ed0 4<\/h2>\n

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

S\u1ed1 ghi d\u01b0\u1edbi m\u1ed7i h\u00ecnh l\u00e0 s\u1ed1 giao \u0111i\u1ec3m m\u00e0 c\u00e1c \u0111\u01b0\u1eddng th\u1eb3ng c\u00f3 trong h\u00ecnh \u0111\u00f3 c\u1eaft nhau. H\u00ecnh th\u1ee9 nh\u1ea5t c\u00f3 1 giao \u0111i\u1ec3m giao nhau, h\u00ecnh th\u1ee9 hai c\u00f3 3 giao \u0111i\u1ec3m giao nhau, h\u00ecnh th\u1ee9 ba c\u00f3 4 giao \u0111i\u1ec3m giao nhau v\u00e0 h\u00ecnh th\u1ee9 t\u01b0 c\u00f3 2 giao \u0111i\u1ec3m giao nhau. V\u1eady s\u1ed1 \u0111i\u1ec1n v\u00e0o d\u1ea5u ch\u1ea5m h\u1ecfi l\u00e0 s\u1ed1 2.<\/p>\n

\"102_1.jpg\"<\/p>\n

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

S\u1ed1 ghi d\u01b0\u1edbi m\u1ed7i h\u00ecnh l\u00e0 s\u1ed1 ph\u1ea7n m\u1eb7t ph\u1eb3ng m\u00e0 c\u00e1c \u0111\u01b0\u1eddng th\u1eb3ng c\u00f3 trong h\u00ecnh \u0111\u00f3 chia ra. H\u00ecnh th\u1ee9 nh\u1ea5t c\u00f3 4 ph\u1ea7n, h\u00ecnh th\u1ee9 hai c\u00f3 7 ph\u1ea7n, h\u00ecnh th\u1ee9 ba c\u00f3 9 ph\u1ea7n v\u00e0 h\u00ecnh th\u1ee9 4 c\u00f3 6 ph\u1ea7n. V\u1eady s\u1ed1 \u0111i\u1ec1n v\u00e0o d\u1ea5u h\u1ecfi ch\u1ea5m l\u00e0 s\u1ed1 6.<\/p>\n

\"102_2.jpg\"<\/p>\n

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

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

Ta chuy\u1ec3n que di\u00eam \u1edf gi\u1eefa s\u1ed1 8 \u0111\u1ec3 c\u00f3 ch\u1eef s\u1ed1 0, l\u1ea5y que di\u00eam \u0111\u00f3 gh\u00e9p v\u00e0o ch\u1eef s\u1ed1 5 c\u1ee7a s\u1ed1 502 \u0111\u1ec3 \u0111\u01b0\u1ee3c s\u1ed1 602.<\/p>\n

L\u1ea5y 1 que di\u00eam \u1edf ch\u1eef s\u1ed1 2 c\u1ee7a s\u1ed1 602 v\u00e0 \u0111\u1eb7t v\u00e0o v\u1ecb tr\u00ed kh\u00e1c c\u1ee7a ch\u1eef s\u1ed1 2 \u0111\u00f3 \u0111\u1ec3 chuy\u1ec3n s\u1ed1 602 th\u00e0nh s\u1ed1 603, ta c\u00f3 ph\u00e9p t\u00ednh \u0111\u00fang:<\/p>\n

\"103.jpg\"<\/p>\n

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

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

N\u00f3 l\u00e0 s\u1ed1 l\u1ebb n\u1eb1m trong ph\u1ea1m vi c\u00e1c s\u1ed1 t\u1ef1 nhi\u00ean t\u1eeb 1 \u0111\u1ebfn 58, khi vi\u1ebft n\u00f3 kh\u00f4ng s\u1eed d\u1ee5ng c\u00e1c ch\u1eef s\u1ed1 1; 2; 3 n\u00ean n\u00f3 c\u00f3 th\u1ec3 l\u00e0: 5; 7; 9; 45; 47; 49; 55; 57.<\/p>\n

Nh\u01b0ng n\u00f3 kh\u00f4ng chia h\u1ebft cho 3; 5; 7 n\u00ean trong c\u00e1c s\u1ed1 tr\u00ean ch\u1ec9 c\u00f3 s\u1ed1 47 l\u00e0 th\u1ecfa m\u00e3n. V\u1eady n\u00f3 l\u00e0 s\u1ed1 47.<\/p>\n

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

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

C\u00f3 m\u1ed7i m\u1ed9t que di\u00eam th\u00ec l\u00e0m sao m\u00e0 th\u1eafp? Qu\u1ec7t v\u00e0o t\u01b0\u1eddng l\u00e0m sao ch\u00e1y? N\u00ean kh\u00f4ng th\u1eafp \u0111\u01b0\u1ee3c.<\/p>\n

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

H\u01b0\u1edbng d\u1eabn:<\/p>\n\n\n\n\n
A: 2<\/td>\nB – 1<\/td>\nC: 2<\/td>\nD – 2<\/td>\n<\/tr>\n
E: 2<\/td>\nG – 3 H<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\"104.jpg\"<\/p>\n

Ta d\u00f9ng l\u01b0u \u0111\u1ed3 tr\u00ean \u0111\u1ec3 nghi\u00ean c\u1ee9u b\u00e0i to\u00e1n:<\/p>\n

– V\u00f2ng tr\u00f2n A ch\u1ec9 s\u1ed1 m\u1eadn l\u00fac \u0111\u1ea7u.<\/p>\n

– V\u00f2ng tr\u00f2n B ch\u1ec9 s\u1ed1 m\u1eadn c\u00f2n l\u1ea1i sau khi \u0111\u00e3 cho b\u1edbt m\u1ed9t n\u1eeda.<\/p>\n

– V\u00f2ng tr\u00f2n C ch\u1ec9 s\u1ed1 m\u1eadn c\u00f2n l\u1ea1i sau khi \u0111\u00e3 cho b\u1edbt m\u1ed9t qu\u1ea3 n\u1eefa.<\/p>\n

– V\u00f2ng tr\u00f2n D ch\u1ec9 s\u1ed1 m\u1eadn c\u00f2n l\u1ea1i sau khi \u0111\u00e3 cho b\u1edbt m\u1ed9t n\u1eeda n\u1eefa.<\/p>\n

…<\/p>\n

Ta th\u1ea5y r\u1eb1ng: A : 2 = B<\/p>\n

V\u1eady ta vi\u1ebft d\u1ea5u \u201c: 2\u201d l\u00ean b\u00ean tr\u00ean m\u0169i t\u00ean n\u1ed1i t\u1eeb A \u0111\u1ebfn B.<\/p>\n

L\u1ea1i c\u00f3 B \u2013 1 = C<\/p>\n

V\u1eady ta vi\u1ebft d\u1ea5u \u201c- 1\u201d l\u00ean b\u00ean tr\u00ean m\u0169i t\u00ean n\u1ed1i t\u1eeb B \u0111\u1ebfn C.<\/p>\n

…<\/p>\n

C\u1ee9 nh\u01b0 v\u1eady ta c\u00f3 l\u01b0u \u0111\u1ed3 tr\u00ean. Bi\u1ebft r\u1eb1ng h = 0 ta c\u00f3 th\u1ec3 \u0111i ng\u01b0\u1ee3c tr\u1edf l\u1ea1i \u0111\u1ec3 t\u00ecm a b\u1eb1ng c\u00e1ch \u0111\u1ea3o ng\u01b0\u1ee3c c\u00e1c ph\u00e9p t\u00ednh nh\u01b0 sau:<\/p>\n

\"105.jpg\"<\/p>\n\n\n\n\n
34 x 2<\/td>\n17 + 1<\/td>\n16 x 2<\/td>\n<\/tr>\n
8 + 2<\/td>\n6 x 2<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

V\u1eady l\u00fac \u0111\u1ea7u trong gi\u1ecf c\u00f3 34 qu\u1ea3 m\u1eadn.<\/p>\n

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

Sau khi cho ho\u00e0ng t\u1eed th\u1ee9 ba, trong gi\u1ecf c\u00f2n:<\/p>\n

(0 + 3) x 2 = 6 (qu\u1ea3 m\u1eadn)<\/p>\n

Sau khi cho ho\u00e0ng t\u1eed th\u1ee9 hai, trong gi\u1ecf c\u00f2n:<\/p>\n

(6 + 2) x 2 = 16 (qu\u1ea3 m\u1eadn)<\/p>\n

L\u00fac \u0111\u1ea7u trong gi\u1ecf c\u00f3:<\/p>\n

(16 + 1) x 2 = 34 (qu\u1ea3 m\u1eadn)<\/p>\n

\u0110\u00e1p s\u1ed1: 34 (qu\u1ea3 m\u1eadn).<\/p>\n","protected":false},"excerpt":{"rendered":"

C\u00c2U 1: Nh\u00ecn h\u00ecnh \u0111i\u1ec1n s\u1ed1? C\u00c2U 2: B\u1ea1n \u0111o\u00e1n xem s\u1ed1 n\u00e0o nh\u00e9? C\u00c2U 3: B\u1ea1n h\u00e3y di chuy\u1ec3n hai que di\u00eam l\u1ea1i \u0111\u00fang v\u1ecb tr\u00ed \u0111\u1ec3 k\u1ebft qu\u1ea3 ph\u00e9p T\u00ednh l\u00e0 \u0111\u00fang: C\u00c2U 4: S\u1ed1 n\u00e0y n\u1eb1m trong ph\u1ea1m vi c\u00e1c s\u1ed1 t\u1ef1 nhi\u00ean t\u1eeb 1 \u0111\u1ebfn 58. Khi vi\u1ebft “n\u00f3” kh\u00f4ng s\u1eed […]<\/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-25454","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\/25454","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=25454"}],"version-history":[{"count":1,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/25454\/revisions"}],"predecessor-version":[{"id":25463,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/25454\/revisions\/25463"}],"wp:attachment":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/media?parent=25454"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/categories?post=25454"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/tags?post=25454"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}