C\u00f3 ng\u01b0\u1eddi c\u00f3 kh\u1ea3 n\u0103ng t\u00ednh nh\u1ea9m r\u1ea5t nhanh nh\u1edd \u0111\u00f3 h\u1ecd c\u00f3 th\u1ec3 cho \u0111\u01b0\u1ee3c nh\u1eefng \u0111\u00e1p \u00e1n \u0111\u00fang, nhanh c\u00e1c v\u1ea5n \u0111\u1ec1, c\u00e1c \u0111\u1ec1 \u00e1n ph\u1ee9c t\u1ea1p. \u0110\u1ec3 c\u00f3 th\u1ec3 c\u00f3 k\u0129 n\u0103ng t\u00ednh nhanh ngo\u00e0i vi\u1ec7c c\u00f3 nh\u1ea1y c\u1ea3m v\u1edbi c\u00e1c con s\u1ed1, c\u00f3 tr\u00ed nh\u1edb t\u1ed1t, c\u00f2n ph\u1ea3i bi\u1ebft c\u00e1c quy t\u1eafc v\u00e0 tr\u1ea3i qua r\u00e8n luy\u1ec7n, luy\u1ec7n t\u1eadp.<\/p>\n\n\n\n
Sau \u0111\u00e2y l\u00e0 v\u00e0i quy t\u1eafc t\u00ednh nhanh m\u1ed9t s\u1ed1 d\u1ea1ng t\u00edch s\u1ed1.<\/p>\n\n\n\n
Gi\u1ea3 s\u1eed c\u1ea7n t\u00ednh t\u00edch s\u1ed1 c\u1ee7a hai s\u1ed1 c\u00f3 \u0111\u1eb7c \u0111i\u1ec3m c\u00f3 ch\u1eef s\u1ed1 h\u00e0ng ch\u1ee5c gi\u1ed1ng nhau v\u00e0 t\u1ed5ng c\u00e1c ch\u1eef s\u1ed1 h\u00e0ng \u0111\u01a1n v\u1ecb b\u1eb1ng 10.<\/p>\n\n\n\n
V\u00ed d\u1ee5 c\u1ea7n t\u00ednh t\u00edch s\u1ed1 74 x 76 = ?<\/p>\n\n\n\n
Ta t\u00ednh t\u00edch c\u1ee7a ch\u1eef s\u1ed1 h\u00e0ng ch\u1ee5c nh\u00e2n v\u1edbi ch\u1eef s\u1ed1 h\u00e0ng ch\u1ee5c + 1, t\u1ee9c l\u00e0 t\u00edch 7 x (7 + 1) = 7 x 8 = 56. Sau \u0111\u00f3 l\u1eadp t\u00edch s\u1ed1 c\u1ee7a hai ch\u1eef s\u1ed1 h\u00e0ng \u0111\u01a1n v\u1ecb t\u1ee9c 6 x 4 = 24. \u0110\u1eb7t hai t\u00edch s\u1ed1 thu \u0111\u01b0\u1ee3c k\u1ebf ti\u1ebfp nhau v\u00e0 thu \u0111\u01b0\u1ee3c s\u1ed1 5624. \u0110\u00f3 ch\u00ednh l\u00e0 t\u00edch s\u1ed1 c\u1ea7n t\u00ednh. Ta c\u00f3 th\u1ec3 d\u1ec5 d\u00e0ng ch\u1ee9ng minh quy t\u1eafc v\u1eeba \u0111\u01b0a ra.<\/p>\n\n\n\n
Theo \u0111i\u1ec1u ki\u1ec7n \u0111\u1eb7t ra t\u00edch hai s\u1ed1 c\u1ea7n t\u00ednh c\u00f3 th\u1ec3 bi\u1ec3u di\u1ec5n d\u01b0\u1edbi d\u1ea1ng (10a + b)(10a + c) (10a + b)(10a + c) = 100a2 + 10ab + 10ac + bc = 100a2 + 10ab +10a(10 – b) +bc = 100a2 + 10ab + 100a – 10ab + bc = 100a(a + 1) + bc<\/p>\n\n\n\n
Ta c\u00f3 th\u1ec3 m\u1edf r\u1ed9ng quy t\u1eafc n\u00e0y cho t\u00edch c\u1ee7a c\u00e1c s\u1ed1 c\u00f3 nhi\u1ec1u ch\u1eef s\u1ed1 h\u01a1n. V\u00ed d\u1ee5 t\u00ednh t\u00edch s\u1ed1 497 x 493 = ?<\/p>\n\n\n\n
D\u1ef1a v\u00e0o quy t\u1eafc \u0111\u00e3 n\u00eau, tr\u01b0\u1edbc h\u1ebft ta t\u00ednh 49 x 50 = 2450 v\u00e0 7 x 3 = 21.<\/p>\n\n\n\n
V\u00e0 t\u00edch s\u1ed1 c\u1ea7n t\u00ednh s\u1ebd l\u00e0 245021.<\/p>\n\n\n\n
C\u00f3 r\u1ea5t nhi\u1ec1u lo\u1ea1i quy t\u1eafc t\u00ednh nhanh, \u0111\u1ec3 \u1ee9ng d\u1ee5ng t\u1ed1t c\u00e1c quy t\u1eafc c\u1ea7n c\u00f3 s\u1ef1 quan s\u00e1t v\u00e0 c\u1ea3m nh\u1eadn nhanh, nh\u1ea1y c\u00e1c con s\u1ed1. N\u1ebfu kh\u00f4ng th\u00ec d\u00f9 \u0111\u00e3 bi\u1ebft r\u00f5 c\u00e1c quy t\u1eafc th\u00ec c\u0169ng kh\u00f4ng k\u1ecbp nh\u1eadn d\u1ea1ng v\u00e0 s\u1eed d\u1ee5ng quy t\u1eafc \u0111\u00fang ch\u1ed7 v\u00e0 s\u1ebd kh\u00f4ng \u0111\u00e1p \u1ee9ng \u0111\u01b0\u1ee3c y\u00eau c\u1ea7u t\u00ednh nhanh, th\u1eadm ch\u00ed c\u00f3 khi s\u1eed d\u1ee5ng quy t\u1eafc t\u00ednh nhanh l\u1ea1i kh\u00f4ng nhanh h\u01a1n c\u00e1ch t\u00ednh to\u00e1n th\u00f4ng th\u01b0\u1eddng nhi\u1ec1u l\u1eafm.<\/p>\n\n\n\n
L\u1ea5y th\u00eam v\u00ed d\u1ee5 kh\u00e1c: Ta c\u1ea7n t\u00ednh t\u00edch s\u1ed1 72548 x 37 = ?<\/p>\n\n\n\n
N\u1ebfu b\u1ea1n ch\u00fa \u00fd m\u1ed9t ch\u00fat s\u1ebd th\u1ea5y 3 l\u1ea7n s\u1ed1 37 l\u00e0 s\u1ed1 111, v\u00ec v\u1eady khi nh\u00e2n m\u1ed9t s\u1ed1 v\u1edbi s\u1ed1 37 c\u00f3 th\u1ec3 l\u1ea5y s\u1ed1 \u0111\u00f3 nh\u00e2n v\u1edbi 111 sau \u0111\u00f3 l\u1ea5y t\u00edch s\u1ed1 v\u1eeba t\u00ednh chia 3, k\u1ebft qu\u1ea3 s\u1ebd cho ta t\u00edch s\u1ed1 c\u1ea7n t\u00ednh. Vi\u1ec7c nh\u00e2n m\u1ed9t s\u1ed1 v\u1edbi 111 kh\u00e1 \u0111\u01a1n gi\u1ea3n.<\/p>\n\n\n\n
Th\u1ef1c hi\u1ec7n ph\u00e9p nh\u00e2n v\u1edbi 111 v\u00e0 72548 x 37 = 2684276.<\/p>\n\n\n\n
R\u00f5 r\u00e0ng \u1edf \u0111\u00e2y tr\u00ed nh\u1edb c\u00f3 vai tr\u00f2 h\u1ebft s\u1ee9c quan tr\u1ecdng. Mu\u1ed1n c\u00f3 tr\u00ed nh\u1edb t\u1ed1t ph\u1ea3i tr\u1ea3i qua luy\u1ec7n t\u1eadp. C\u00f3 nh\u1eefng ng\u01b0\u1eddi c\u00f3 k\u0129 n\u0103ng t\u00ednh nhanh k\u00ec t\u00e0i, h\u1ecd c\u00f3 th\u1ec3 nh\u1edb ch\u00ednh x\u00e1c \u0111\u1ea7y \u0111\u1ee7 b\u00ecnh ph\u01b0\u01a1ng c\u1ee7a 1000 s\u1ed1 nguy\u00ean \u0111\u1ea7u ti\u00ean.<\/p>\n\n\n\n
M\u1ecdi b\u00e0i to\u00e1n \u0111\u1ec1u c\u00f3 th\u1ec3 t\u00ednh nhanh, vi\u1ec7c t\u00ednh to\u00e1n c\u00f3 th\u1ec3 theo c\u00e1c quy t\u1eafc kh\u00e1c nhau, t\u1ed1c \u0111\u1ed9 t\u00ednh to\u00e1n ph\u1ee5 thu\u1ed9c nhi\u1ec1u v\u00e0o vi\u1ec7c s\u1eed d\u1ee5ng h\u1ee3p l\u00ed c\u00e1c quy t\u1eafc v\u00e0 ph\u1ea3i th\u00f4ng qua qu\u00e1 tr\u00ecnh r\u00e8n luy\u1ec7n m\u1edbi thu \u0111\u01b0\u1ee3c k\u1ebft qu\u1ea3 t\u1ed1t.<\/p>\n\n\n\n
T\u1eeb kho\u00e1: T\u00ednh nhanh.<\/p>\n\n\n\n
<\/p>\n\n\n\n\n\n\n","protected":false},"excerpt":{"rendered":"
C\u00f3 ng\u01b0\u1eddi c\u00f3 kh\u1ea3 n\u0103ng t\u00ednh nh\u1ea9m r\u1ea5t nhanh nh\u1edd \u0111\u00f3 h\u1ecd c\u00f3 th\u1ec3 cho \u0111\u01b0\u1ee3c nh\u1eefng \u0111\u00e1p \u00e1n \u0111\u00fang, nhanh c\u00e1c v\u1ea5n \u0111\u1ec1, c\u00e1c \u0111\u1ec1 \u00e1n ph\u1ee9c t\u1ea1p. \u0110\u1ec3 c\u00f3 th\u1ec3 c\u00f3 k\u0129 n\u0103ng t\u00ednh nhanh ngo\u00e0i vi\u1ec7c c\u00f3 nh\u1ea1y c\u1ea3m v\u1edbi c\u00e1c con s\u1ed1, c\u00f3 tr\u00ed nh\u1edb t\u1ed1t, c\u00f2n ph\u1ea3i bi\u1ebft c\u00e1c quy […]<\/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":[15,9],"tags":[],"class_list":["post-7491","post","type-post","status-publish","format-standard","hentry","category-hoi-dap-khoa-hoc","category-toan-hoc"],"_links":{"self":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/7491","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=7491"}],"version-history":[{"count":0,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/7491\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/media?parent=7491"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/categories?post=7491"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/tags?post=7491"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}