C\u00e1c lo\u1ea1i d\u00e0n \u0111\u1ec1 l\u00e0 m\u1ed9t thu\u1eadt ng\u1eef chuy\u00ean m\u00f4n \u0111\u01b0\u1ee3c d\u00f9ng trong l\u00f4 \u0111\u1ec1 h\u1ecdc, \u0111\u1ec3 c\u00f3 th\u1ec3 \u0111\u00e1nh \u0111\u01b0\u1ee3c d\u00e0n \u0111\u1ec1 th\u00ec ng\u01b0\u1eddi ch\u01a1i c\u1ea7n n\u1eafm ch\u1eafc \u0111\u01b0\u1ee3c \u0111\u1ecbnh ngh\u0129a v\u00e0 ph\u00e2n bi\u1ec7t c\u00e1c lo\u1ea1i d\u00e0n \u0111\u1ec1 khi ch\u01a1i.<\/p>\n
<\/p>\n
\u2705 1. D\u00e0n l\u00f4 \u0111\u1ec1 l\u00e0 g\u00ec?<\/h2>\n
D\u00e0n c\u00f3 ngh\u0129a l\u00e0 s\u1ed1 nhi\u1ec1u, th\u01b0\u1eddng th\u00ec trong l\u00f4 \u0111\u1ec1 x\u1ed5 s\u1ed1, d\u00e0n l\u00e0 m\u1ed9t t\u1eadp h\u1ee3p bao g\u1ed3m 10 c\u1eb7p s\u1ed1 tr\u1edf l\u00ean.<\/p>\n
Trong l\u00f4 \u0111\u1ec1 th\u00ec c\u00f3 d\u00e0n \u0111\u1ec1 v\u00e0 d\u00e0n l\u00f4, nhi\u1ec1u ng\u01b0\u1eddi l\u1ef1a ch\u1ecdn ch\u01a1i d\u00e0n trong ng\u00e0y, theo tu\u1ea7n v\u00ec t\u1ef7 l\u1ec7 tr\u00fang d\u00e0n cao h\u01a1n ch\u01a1i \u0111\u1ec1 b\u1ea1ch th\u1ee7 hay l\u00f4 \u0111\u1ed9c th\u1ee7. B\u00ean c\u1ea1nh \u0111\u00f3 c\u0169ng c\u00f3 c\u00e1c lo\u1ea1i d\u00e0n \u0111\u1ec1 \u0111\u00e1nh quanh n\u0103m \u0111\u01b0\u1ee3c nhi\u1ec1u l\u00f4 th\u1ee7 l\u1ef1a ch\u1ecdn th\u01b0\u1eddng xuy\u00ean \u00e1p d\u1ee5ng.<\/p>\n
D\u00e0n \u0111\u1ec1 ng\u00e0y h\u00f4m nay n\u00ean \u0111\u00e1nh b\u1ed9 s\u1ed1 n\u00e0o l\u00e0 m\u1ed9t trong nh\u1eefng v\u1ea5n \u0111\u1ec1 khi\u1ebfn nhi\u1ec1u ng\u01b0\u1eddi ch\u01a1i \u0111au \u0111\u1ea7u. D\u01b0\u1edbi \u0111\u00e2y trang s\u1ebd \u0111\u01b0a ra nh\u1eefng b\u1ed9 d\u00e0n t\u1ed5ng h\u1ee3p nh\u1ea5t t\u1eeb tr\u01b0\u1edbc t\u1edbi nay cho anh ch\u1ecb em hi\u1ec3u r\u00f5 h\u01a1n.<\/p>\n
\u2705 2. C\u00e1c d\u00e0n l\u00f4 \u0111\u1ec1 theo t\u1ed5ng c\u1eb7p s\u1ed1<\/h2>\n
Ng\u01b0\u1eddi ch\u01a1i c\u00f3 th\u1ec3 l\u1ef1a ch\u1ecdn d\u00e0n \u0111\u1ec1 \u0111\u00e1nh h\u00e0ng ng\u00e0y theo t\u1ed5ng v\u1ec1, c\u1ee5 th\u1ec3 nh\u01b0:<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 t\u1ed5ng 0: 19, 91, 28, 82, 37, 73, 46, 64, 55, 00,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 t\u1ed5ng 1: 01,10, 29, 92, 38, 83, 47, 74, 56, 65,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 t\u1ed5ng 2: 02, 20, 39, 93, 48, 84, 57, 75, 11, 66,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 t\u1ed5ng 3: 03, 30, 12, 21, 49, 94, 58, 85, 67, 76,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 t\u1ed5ng 4: 04, 40, 13, 31, 59, 95, 68, 86, 22, 77,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 t\u1ed5ng 5: 05, 50, 14, 41, 23, 32, 69, 96, 78, 87,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 t\u1ed5ng 6: 06, 60, 15, 51, 24, 42, 79, 97, 33, 88,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 t\u1ed5ng 7: 07, 70, 16, 61, 25, 52, 34, 43, 89, 98,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 t\u1ed5ng 8: 08, 80, 17, 71, 26, 62, 35, 53, 44, 99,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 t\u1ed5ng 9: 09, 90, 18, 81, 27, 72, 36, 63, 45, 54,<\/p>\n
\u2705 3. C\u00e1c d\u00e0n \u0111\u1ec1 \u0111\u1eb7c bi\u1ec7t theo \u0111\u1ea7u:<\/h2>\n
D\u00e0n \u0111\u1eb7c bi\u1ec7t h\u00e0ng ng\u00e0y theo \u0111\u1ea7u c\u0169ng l\u00e0 m\u1ed9t trong c\u00e1c lo\u1ea1i d\u00e0n \u0111\u1ec1 m\u00e0 c\u00e1c l\u00f4 th\u1ee7 l\u1ef1a ch\u1ecdn nhi\u1ec1u. Ng\u01b0\u1eddi ch\u01a1i c\u00f3 th\u1ec3 \u00e1p d\u1ee5ng l\u00e0m d\u00e0n \u0111\u1ec1 chu\u1ea9n \u0111\u00e1nh quanh n\u0103m. V\u1eady c\u00e1c lo\u1ea1i d\u00e0n \u0111\u1ec1 \u0111\u1eb7c bi\u1ec7t theo \u0111\u1ea7u c\u1ee5 th\u1ec3 nh\u01b0:<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 \u0111\u1ea7u 0: 00, 01, 02, 03, 04, 05, 06, 07, 08, 09,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 \u0111\u1ea7u 1: 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 \u0111\u1ea7u 2: 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 \u0111\u1ea7u 3: 30, 31, 32, 33, 34, 35, 36, 37, 38, 39,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 \u0111\u1ea7u 4: 40, 41, 42, 43, 44, 45, 46, 47, 48, 49,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 \u0111\u1ea7u 5: 50, 51, 52, 53, 54, 55, 56, 57, 58, 59,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 \u0111\u1ea7u 6: 60, 61, 62, 63, 64, 65, 66, 67, 68, 69,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 \u0111\u1ea7u 7: 70, 71, 72, 73, 74, 75, 76, 77, 78, 79,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 \u0111\u1ea7u 8: 80, 81, 82, 83, 84, 85, 86, 87, 88, 89,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 \u0111\u1ea7u 9: 90, 91, 92, 93, 94, 95, 96, 97, 98, 99,<\/p>\n
\u2705 4. C\u00e1c d\u00e0n l\u00f4 \u0111\u1ec1 theo \u0111u\u00f4i:<\/h2>\n
<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 \u0111u\u00f4i 0: 00,10, 20, 30, 40, 50, 60, 70, 80, 90,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 \u0111u\u00f4i 1: 01, 11, 21, 31, 41, 51, 61, 71, 81, 91,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 \u0111u\u00f4i 2: 02, 12, 22, 32, 42, 52, 62, 72, 82, 92,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 \u0111u\u00f4i 3: 03, 13, 23, 33, 43, 53, 63, 73, 83, 93,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 \u0111u\u00f4i 4: 04, 14, 24, 34, 44, 54, 64, 74, 84, 94,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 \u0111u\u00f4i 5: 05, 15, 25, 35, 45, 55, 65, 75, 85, 95,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 \u0111u\u00f4i 6: 06, 16, 26, 36, 46, 56, 66, 76, 86, 96,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 \u0111u\u00f4i 7: 07, 17, 27, 37, 47, 57, 67, 77, 87, 97,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 \u0111u\u00f4i 8: 08, 18, 28, 38, 48, 58, 68, 78, 88, 98,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 \u0111u\u00f4i 9: 09, 19, 29, 39, 49, 59, 69, 79, 89, 99,<\/p>\n
\u2705 5. C\u00e1c d\u00e0n trong l\u00f4 \u0111\u1ec1 theo b\u1ed9 s\u1ed1:<\/h2>\n
B\u1ed9 s\u1ed1 l\u00f4 \u0111\u1ec1 \u0111\u01b0\u1ee3c hi\u1ec3u \u0111\u01a1n gi\u1ea3n l\u00e0 c\u00e1c c\u1eb7p s\u1ed1 c\u00f3 2 ch\u1eef s\u1ed1 hay \u0111i c\u00f9ng nhau. D\u1ef1a v\u00e0o c\u00e1c b\u1ed9 s\u1ed1 n\u00e0y m\u00e0 x\u00e2y d\u1ef1ng l\u00ean c\u00e1c d\u00e0n l\u00f4 \u0111\u1ec1 \u0111\u1eb9p hay \u0111\u00e1nh, c\u1ee5 th\u1ec3 nh\u01b0:<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 theo b\u1ed9 00: 00, 55, 05, 50,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 theo b\u1ed9 11: 11, 66, 16, 61,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 theo b\u1ed9 22: 22, 77, 27, 72,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 theo b\u1ed9 33: 33, 88, 38, 83,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 theo b\u1ed9 44: 44, 99, 49, 94,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 theo b\u1ed9 01: 01, 10, 06, 60, 51, 15, 56, 65,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 theo b\u1ed9 02: 02, 20, 07, 70, 25, 52, 57, 75,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 theo b\u1ed9 03: 03, 30, 08, 80, 35, 53, 58, 85,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 theo b\u1ed9 04: 04, 40, 09, 90, 45, 54, 59, 95,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 theo b\u1ed9 12: 12, 21, 17, 71, 26, 62, 67, 76,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 theo b\u1ed9 13: 13, 31, 18, 81, 36, 63, 68, 86,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 theo b\u1ed9 14: 14, 41, 19, 91, 46, 64, 69, 96,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 theo b\u1ed9 23: 23, 32, 28, 82, 73, 37, 78, 87,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 theo b\u1ed9 24: 24, 42, 29, 92, 74, 47, 79, 97,<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 theo b\u1ed9 34: 34, 43, 39, 93, 84, 48, 89, 98,<\/p>\n
\u2705 6. C\u00e1c lo\u1ea1i d\u00e0n \u0111\u1ec1 x\u1ebfp theo ch\u1ea1m:<\/h2>\n
Ch\u1ea1m t\u1ee9c l\u00e0 t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 c\u00f3 d\u00ednh s\u1ed1 \u0111\u00f3. Ch\u00fang ta c\u00f3 10 s\u1ed1 t\u1ef1 nhi\u00ean t\u1eeb 0 \u2013 9, t\u01b0\u01a1ng \u1ee9ng v\u1edbi 10 s\u1ed1 n\u00e0y s\u1ebd c\u00f3 10 d\u00e0n \u0111\u1ec1 ch\u1ea1m theo th\u1ee9 t\u1ef1. V\u00ed d\u1ee5 nh\u01b0 ch\u1ea1m 0 ngh\u0129a l\u00e0 t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 c\u00f3 \u0111\u1ea7u 0 v\u00e0 \u0111\u00edt 0.<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 theo c\u1ea7u ch\u1ea1m 0: 01, 10, 02, 20, 03, 30, 04, 40, 05, 50, 06, 60, 07, 70, 08, 80, 09, 90, 00<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 theo c\u1ea7u ch\u1ea1m 1: 01, 10, 12, 21, 13, 31, 14, 41, 15, 51, 16, 61, 17, 71, 18, 81, 19, 91, 11<\/p>\n
\u2b50 D\u00e0n l\u00f4 \u0111\u1ec1 theo c\u1ea7u ch\u1ea1m 2: 02, 20, 12, 21, 23, 32, 24, 42, 25, 52, 26, 62, 27, 72, 28, 82, 29, 92, 22<\/p>\n
<\/p>\n
\u2705 7. C\u00e1c lo\u1ea1i d\u00e0n \u0111\u1ec1 25 s\u1ed1<\/h2>\n
D\u00e0n \u0111\u1ec1 25 l\u00e0 m\u1ed9t trong nh\u1eefng lo\u1ea1i d\u00e0n \u0111\u1ec1 t\u1ed5ng h\u1ee3p \u0111a d\u1ea1ng v\u00e0 hi\u1ec7u qu\u1ea3 nh\u1ea5t, \u0111\u1eb7c bi\u1ec7t d\u00e0n \u0111\u1ec1 n\u00e0y kh\u00e1 phong ph\u00fa v\u1edbi c\u00e1c lo\u1ea1i d\u00e0n \u0111\u1ec1 25 s\u1ed1 kh\u00e1c nhau nh\u01b0 d\u00e0n l\u00f4 \u0111\u1ec1 ch\u1eb5n ch\u1eb5n 25 s\u1ed1, d\u00e0n l\u00f4 \u0111\u1ec1 l\u1ebb l\u1ebb 25 s\u1ed1, \u2026. C\u1ee5 th\u1ec3 t\u1eebng lo\u1ea1i nh\u01b0 sau:<\/p>\n
\u2b50 7.1. D\u00e0n l\u00f4 \u0111\u1ec1 Ch\u1eb5n Ch\u1eb5n 25 s\u1ed1<\/h3>\n
C\u00f3 max 35 ng\u00e0y, t\u1ea7n su\u1ea5t 8-12 ng\u00e0y bao g\u1ed3m c\u00e1c c\u1eb7p s\u1ed1:<\/p>\n
00, 22, 44, 66, 88, 02, 20, 04, 40, 06, 60, 08, 80, 24, 42, 26, 62 , 28, 82, 46, 64, 48, 84, 68, 86<\/p>\n
\u2b50 7.2. D\u00e0n l\u00f4 \u0111\u1ec1 L\u1ebb L\u1ebb 25 s\u1ed1<\/h3>\n
C\u00f3 max 28 ng\u00e0y, t\u1ea7n su\u1ea5t 8-12 ng\u00e0y bao g\u1ed3m c\u00e1c c\u1eb7p s\u1ed1:<\/p>\n
11, 33, 55, 77, 99, 13, 31, 15, 51, 17, 71, 19, 91, 35, 53, 37, 73 , 39, 93, 57, 75, 59, 95, 79, 97<\/p>\n
\u2b50 7.3. D\u00e0n \u0111\u1ec1 Ch\u1eb5n L\u1ebb 25 s\u1ed1<\/h3>\n
C\u00f3 max 31 ng\u00e0y, t\u1ea7n su\u1ea5t 8-12 ng\u00e0y bao g\u1ed3m c\u00e1c c\u1eb7p s\u1ed1:<\/p>\n
01, 03, 05, 07, 09, 21, 23, 25, 27, 29, 41, 43, 45, 47, 49, 61, 63 , 65, 67, 69, 81, 83, 85, 87, 89<\/p>\n
\u2b50 7.4. D\u00e0n l\u00f4 \u0111\u1ec1 L\u1ebb Ch\u1eb5n 25 s\u1ed1<\/h3>\n
C\u00f3 max 30 ng\u00e0y, t\u1ea7n su\u1ea5t 8-12 ng\u00e0y bao g\u1ed3m c\u00e1c c\u1eb7p s\u1ed1:<\/p>\n
10, 12, 14, 16, 18, 30, 32, 34, 36, 38, 50, 52, 54, 56, 58, 70, 72 , 74, 76, 78, 90, 92, 94, 96, 98<\/p>\n
\u2b50 7.5. D\u00e0n l\u00f4 \u0111\u1ec1 Nh\u1ecf Nh\u1ecf 25 s\u1ed1<\/h3>\n
C\u00f3 max 23 ng\u00e0y, t\u1ea7n su\u1ea5t 8-12 ng\u00e0y bao g\u1ed3m:<\/p>\n
00, 11, 22, 33, 44, 01, 10, 02, 20, 03, 30, 04, 40, 12, 21, 13, 31 , 14, 41, 23, 32, 24, 42, 34, 43<\/p>\n
\u2b50 7.6. D\u00e0n l\u00f4 \u0111\u1ec1 To To 25 s\u1ed1<\/h3>\n
C\u00f3 max 22 ng\u00e0y, t\u1ea7n su\u1ea5t 8-12 ng\u00e0y bao g\u1ed3m:<\/p>\n
55, 66, 77, 88, 99, 56, 65, 57, 75, 58, 85, 59, 95, 67, 76, 68, 86 , 69, 96, 78, 87, 79, 97, 89, 98<\/p>\n
\u2b50 7.7. D\u00e0n l\u00f4 \u0111\u1ec1 Nh\u1ecf To 25 s\u1ed1<\/h3>\n
C\u00f3 max 31 ng\u00e0y, t\u1ea7n su\u1ea5t 8-12 ng\u00e0y g\u1ed3m:<\/p>\n
05, 06, 07, 08, 09, 15, 16, 17, 18, 19, 25, 26, 27, 28, 29, 35, 36 , 37, 38, 39, 45, 46, 47, 48, 49<\/p>\n
\u2b50 7.8. D\u00e0n l\u00f4 \u0111\u1ec1 To Nh\u1ecf 25 s\u1ed1<\/h3>\n
C\u00f3 max 33 ng\u00e0y, t\u1ea7n su\u1ea5t 8-12 ng\u00e0y g\u1ed3m:<\/p>\n
90, 91, 92, 93, 94, 80, 81, 82, 83, 84, 70, 71, 72, 73, 74, 60, 61 , 62, 63, 64, 50, 51, 52, 53, 54<\/p>\n
\u2705 8. D\u00e0n l\u00f4 \u0111\u1ec1 chia Ba 34 s\u1ed1<\/h2>\n
C\u00f3 max 18 ng\u00e0y, t\u1ea7n su\u1ea5t 7-10 ng\u00e0y g\u1ed3m:<\/p>\n
00, 03, 06, 09, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48, 51, 54, 57, 60, 63, 66, 69, 72, 75, 78, 81, 84, 87, 90, 93, 96, 99<\/p>\n<\/div>\n