Trong c\u00e1c c\u00e1ch soi c\u1ea7u l\u00f4 \u0111\u1ec1 th\u00ec c\u00f3 1 c\u00e1ch \u0111\u00e1nh r\u1ea5t hay \u0111\u01b0\u1ee3c c\u00e1c d\u00e2n ch\u01a1i d\u00e0n l\u00f4 \u0111\u1ec1 \u0111\u1eb7c bi\u1ec7t d\u00e0n l\u00f4 tr\u01b0\u1ee3t \u00e1p d\u1ee5ng. \u0110\u00f3 l\u00e0 \u0111\u00e1nh theo c\u00e1c b\u1ed9 s\u1ed1 \u0111\u1ec1 hay c\u00f2n g\u1ecdi l\u00e0 t\u1ed5ng \u0111\u1ec1. C\u00e1ch \u0111\u00e1nh theo t\u1ed5ng \u0111\u1ec1 th\u01b0\u1eddng \u0111\u01b0\u1ee3c \u00e1p d\u1ee5ng cho t\u1ed5ng h\u1ee3p \u0111\u1ec1 mi\u1ec1n B\u1eafc l\u00e0 ch\u1ee7 y\u1ebfu. Do \u0111\u00f3 anh em c\u00f3 th\u1ec3 coi nh\u01b0 b\u00e0i vi\u1ebft n\u00e0y h\u01b0\u1edbng d\u1eabn c\u00e1ch \u0111\u00e1nh v\u00e0 th\u1ed1ng k\u00ea t\u1ed5ng l\u00f4 \u0111\u1ec1 XSMB, XSMT, XSMN. Soi C\u1ea7u 3 Mi\u1ec1n xin \u0111\u01b0\u1ee3c g\u1eedi t\u1edbi cho anh em b\u00e0i vi\u1ebft chi ti\u1ebft v\u1ec1 t\u1ea5t c\u1ea3 c\u00e1c b\u1ed9 s\u1ed1 trong l\u00f4 \u0111\u1ec1 c\u00f9ng v\u1edbi c\u00e1ch b\u1eaft s\u1ed1 t\u1ed5ng b\u1ed9 \u0111\u1ec1 \u2013 1 trong nh\u1eefng ph\u01b0\u01a1ng ph\u00e1p soi c\u1ea7u ch\u00ednh x\u00e1c 100 ph\u1ed5 bi\u1ebfn nh\u1ea5t, \u00edt t\u1ed1n th\u1eddi gian suy ngh\u0129, t\u00ednh to\u00e1n m\u00e0 t\u1ec9 l\u1ec7 v\u1ec1 t\u01b0\u01a1ng \u0111\u1ed1i cao.<\/p>\n
<\/span>B\u1ea3ng s\u1ed1 \u0111\u1ec1<\/h2>\nB\u1ea3ng s\u1ed1 \u0111\u1ec1 hay c\u00f2n g\u1ecdi l\u00e0 C\u00e1c b\u1ed9 s\u1ed1 trong l\u00f4 \u0111\u1ec1 hay B\u1ea3ng s\u1ed1 \u0111\u1ec1 l\u00e0 nh\u1eefng ghi ch\u00e9p v\u1ec1 c\u00e1c b\u1ed9 s\u1ed1 \u0111\u1ec1 c\u00f3 chung m\u1ed9t \u0111\u1eb7c \u0111i\u1ec3m khi\u1ebfn ng\u01b0\u1eddi ta tin r\u1eb1ng ch\u00fang s\u1ebd v\u1ec1 c\u00f9ng nhau. Trong l\u00f4 \u0111\u1ec1 c\u00f3 r\u1ea5t nhi\u1ec1u b\u1ed9 s\u1ed1. Ch\u00fang ta c\u00f3 th\u1ec3 li\u1ec7t k\u00ea c\u00e1c b\u1ed9 \u0111\u1ec1 x\u1ed5 s\u1ed1 d\u1ef1a tr\u00ean nh\u1eefng \u0111\u1eb7c \u0111i\u1ec3m nh\u01b0:<\/p>\n
\n- Thu\u1ed9c b\u1ed9 12 con gi\u00e1p<\/li>\n
- C\u00f3 t\u1ed5ng \u0111\u1ec1 gi\u1ed1ng nhau<\/li>\n
- B\u1ed9 s\u1ed1 d\u1ef1a theo b\u00f3ng \u00e2m d\u01b0\u01a1ng ng\u0169 h\u00e0nh<\/li>\n<\/ul>\n
D\u01b0\u1edbi \u0111\u00e2y ch\u00fang ta s\u1ebd c\u00f9ng \u0111i v\u00e0o t\u00ecm hi\u1ec3u t\u1eebng b\u1ed9 s\u1ed1 v\u00e0 y\u1ebfu t\u1ed1 \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh ch\u00fang.<\/p>\n
<\/span>B\u1ed9 15 s\u1ed1<\/h3>\n\u0110\u00e2y l\u00e0 15 b\u1ed9 s\u1ed1 c\u01a1 b\u1ea3n trong l\u00f4 \u0111\u1ec1. Tr\u01b0\u1edbc h\u1ebft, c\u00e1c b\u1ed9 s\u1ed1 trong s\u1ed1 \u0111\u1ec1 n\u00e0y \u0111\u01b0\u1ee3c lu\u1eadn d\u1ef1a theo quy t\u1eafc c\u1eb7p l\u1ed9n v\u00e0 b\u00f3ng d\u01b0\u01a1ng. Nh\u01b0 ch\u00fang ta c\u0169ng \u0111\u00e3 bi\u1ebft, \u0111\u1ec3 t\u00ednh \u0111\u01b0\u1ee3c b\u00f3ng d\u01b0\u01a1ng c\u1ee7a s\u1ed1, ta c\u1ed9ng th\u00eam v\u00e0o s\u1ed1 \u0111\u00f3 05, 50 ho\u1eb7c 55. C\u00f2n c\u00e1c b\u1ed9 s\u1ed1 l\u1ed9n th\u00ec c\u00f3 d\u1ea1ng AB \u2013 BA.<\/p>\n
V\u00ed d\u1ee5 nh\u01b0 B\u1ed9 s\u1ed1 01: Ta c\u00f3 s\u1ed1 l\u1ed9n c\u1ee7a n\u00f3 l\u00e0 10. S\u1ed1 b\u00f3ng d\u01b0\u01a1ng c\u1ee7a n\u00f3 l\u00e0 01, 10, 06, 60, 51, 15, 56, 65.<\/p>\n
D\u1ef1a theo quy t\u1eafc b\u00f3ng d\u01b0\u01a1ng v\u00e0 b\u1ed9 s\u1ed1 l\u1ed9n n\u00e0y, ta c\u00f3 c\u00e1c b\u1ed9 s\u1ed1 trong l\u00f4 \u0111\u1ec1 x\u1ebfp theo b\u1ed9 s\u1ed1 nh\u01b0 sau:<\/p>\n
D\u01b0\u1edbi \u0111\u00e2y ch\u00fang ta s\u1ebd c\u00f9ng \u0111i v\u00e0o t\u00ecm hi\u1ec3u t\u1eebng b\u1ed9 s\u1ed1 v\u00e0 y\u1ebfu t\u1ed1 \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh ch\u00fang.<\/p>\n