K\u00e9p l\u1ec7ch, k\u00e9p b\u1eb1ng, s\u00e1t k\u00e9p, k\u00e9p \u00e2m l\u00e0 g\u00ec l\u00e0 v\u1ea5n \u0111\u1ec1 m\u00e0 nhi\u1ec1u ng\u01b0\u1eddi trong l\u00e0ng l\u00f4 \u0111\u1ec1. C\u00f9ng gi\u1ea3i \u0111\u00e1p t\u1ea5t c\u1ea3 nh\u1eefng kh\u00e1i ni\u1ec7m, c\u00e1ch ch\u01a1i, c\u00e1ch soi n\u00e0y trong b\u00e0i vi\u1ebft!<\/div>\n
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K\u00e9p l\u1ec7ch <\/strong>k\u00e9p l\u1ec7ch g\u1ed3m nh\u1eefng s\u1ed1 n\u00e0o? Ch\u01a1i b\u1ed9 s\u1ed1 k\u00e9p th\u1ebf n\u00e0o \u0111\u1ec3 d\u1ec5 h\u00fap nh\u1ea5t ch\u1eafc h\u1eb3n l\u00e0 th\u1eafc m\u1eafc c\u1ea3u r\u1ea5t nhi\u1ec1u ng\u01b0\u1eddi. B\u00ean c\u1ea1nh \u0111\u00f3, <\/em>b\u1ed9 s\u1ed1 k\u00e9p<\/em><\/strong><\/span> kh\u00e1 quen thu\u1ed9c trong l\u00e0ng l\u00f4 \u0111\u1ec1. Ch\u00fang l\u00e0 nh\u1eefng b\u1ed9 s\u1ed1 c\u1ea7n hi\u1ec3u r\u00f5 khi ch\u01a1i l\u00f4. Th\u1ebf nh\u01b0ng th\u1ef1c t\u1ebf l\u1ea1i c\u00f3 kh\u00f4ng \u00edt ng\u01b0\u1eddi kh\u00f4ng bi\u1ebft b\u1ed9 s\u1ed1 k\u00e9p g\u1ed3m c\u00e1c s\u1ed1 n\u00e0o v\u00e0 c\u00f3 bao nhi\u00eau con, \u0111\u1eb7c bi\u1ec7t l\u00e0 v\u1edbi nh\u1eefng ng\u01b0\u1eddi m\u1edbi ch\u01a1i. Trong b\u00e0i vi\u1ebft n\u00e0y, s\u1ebd c\u00f9ng b\u1ea1n \u0111\u1ecdc gi\u1ea3i \u0111\u00e1p t\u1ea5t t\u1ea7n t\u1eadt v\u1ec1 b\u1ed9 s\u1ed1 k\u00e9p.<\/em><\/span><\/p>\nK\u00e9p l\u1ec7ch \u0111\u01b0\u1ee3c ph\u00e1t tri\u1ec3n t\u1eeb k\u00e9p b\u1eb1ng, ch\u00ednh v\u00ec th\u1ebf tr\u01b0\u1edbc c\u1ea7n ph\u1ea3i t\u00ecm hi\u1ec3u \u0111\u1ecbnh ngh\u0129a v\u1ec1 k\u00e9p b\u1eb1ng.<\/p>\n
1. K\u00e9p b\u1eb1ng<\/strong><\/span><\/h2>\nM\u1ed9t trong nh\u1eefng ki\u1ec3u b\u1ed9 s\u1ed1 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng t\u1eeb r\u1ea5t l\u00e2u \u0111\u1eddi v\u00e0 r\u1ed9ng r\u00e3i trong l\u00f4 \u0111\u1ec1 ch\u00ednh l\u00e0 b\u1ed9 s\u1ed1 k\u00e9p.T\u1eeb t\u00ean g\u1ecdi k\u00e9p b\u1eb1ng, c\u00f3 l\u1ebd \u0111\u00e2u \u0111\u00f3 b\u1ea1n c\u0169ng m\u01b0\u1eddng t\u01b0\u1ee3ng ra r\u1eb1ng k\u00e9p b\u1eb1ng hay b\u1ed9 s\u1ed1 k\u00e9p ch\u00ednh l\u00e0 t\u1ea5t c\u1ea3 nh\u1eefng s\u1ed1 g\u1ed3m 2 ch\u1eef s\u1ed1 gi\u1ed1ng nhau. C\u1ee5 th\u1ec3 c\u00f3 10 b\u1ed9 s\u1ed1 k\u00e9p b\u1eb1ng, \u0111\u00f3 l\u00e0: 00, 11, …, 88, 99.<\/span><\/p>\n2. B\u1ed9 s\u1ed1 k\u00e9p m\u1edf r\u1ed9ng<\/strong><\/span><\/h2>\nD\u1ef1a v\u00e0o k\u00e9p b\u1eb1ng, b\u1eb1ng nh\u1eefng c\u00e1ch kh\u00e1c nhau, ng\u01b0\u1eddi ta m\u1edf r\u1ed9ng ra \u0111\u01b0\u1ee3c c\u00e1c b\u1ed9 s\u1ed1 k\u00e9p l\u1ec7ch, s\u00e1t k\u00e9p v\u00e0 k\u00e9p \u00e2m v\u00ec s\u1ef1 c\u1ea7n thi\u1ebft \u0111\u1ec3 ph\u00e1t tri\u1ec3n s\u00e2n ch\u01a1i l\u00f4 \u0111\u1ec1. Trong ph\u1ea7n ti\u1ebfp theo, ch\u00fang ta s\u1ebd c\u00f9ng t\u00ecm hi\u1ec3u v\u1ec1 nh\u1eefng b\u1ed9 k\u00e9p kh\u00e1c.<\/span><\/p>\n<\/p>\n
3. K\u00e9p l\u1ec7ch l\u00e0 g\u00ec?<\/strong><\/span><\/h2>\nB\u00f3ng d\u01b0\u01a1ng<\/em><\/strong><\/span><\/h3>\nB\u1ed9 k\u00e9p b\u00f3ng d\u01b0\u01a1ng l\u1ec7ch n\u00e0y \u0111\u01b0\u1ee3c m\u1edf r\u1ed9ng d\u1ef1a tr\u00ean \u0111\u1ecbnh ngh\u0129a b\u00f3ng<\/span>. C\u00e1c c\u1eb7p b\u00f3ng bao g\u1ed3m: 0 – 5, 1 – 6, 2 – 7, 3 – 8, 4 – 9. M\u1ed9t quy t\u1eafc \u0111\u01a1n gi\u1ea3n \u0111\u1ec3 nh\u1edb l\u00e2u \u0111\u00f3 l\u00e0: c\u00e1c s\u1ed1 l\u00e0 b\u00f3ng c\u1ee7a nhau khi h\u00e0ng \u0111\u01a1n v\u1ecb h\u01a1n k\u00e9m nhau l\u00e0 5. Nh\u01b0 v\u1eady, c\u00e1c s\u1ed1 l\u00e0 b\u00f3ng c\u1ee7a nhau n\u1ebfu c\u00e1c s\u1ed1 \u0111\u00f3 c\u00f3 1 ch\u1eef s\u1ed1 gi\u1ed1ng nhau v\u00e0 s\u1ed1 c\u00f2n l\u1ea1i l\u00e0 b\u00f3ng c\u1ee7a nhau ho\u1eb7c c\u1ea3 2 ch\u1eef s\u1ed1 trong c\u00e1c s\u1ed1 \u0111\u1ec1u l\u00e0 c\u1eb7p b\u00f3ng. <\/span><\/p>\n\u0110\u1ec3 d\u1ec5 hi\u1ec3u, b\u1ea1n xem v\u00ed d\u1ee5 sau:<\/span><\/p>\n\n- S\u1ed1 52 v\u00e0 57 l\u00e0 b\u00f3ng c\u1ee7a nhau do \u0111\u1ec1u c\u00f3 s\u1ed1 5, c\u00e1c s\u1ed1 c\u00f2n l\u1ea1i c\u1ee7a m\u1ed7i s\u1ed1 l\u00e0 2 v\u00e0 7 l\u00e0 c\u1eb7p b\u00f3ng c\u1ee7a nhau.<\/span><\/li>\n
- S\u1ed1 23 v\u00e0 78 l\u00e0 b\u00f3ng c\u1ee7a nhau do 2 v\u00e0 3 l\u00e0 c\u1eb7p b\u00f3ng c\u1ee7a nhau \u0111\u1ed3ng th\u1eddi 3 v\u00e0 8 l\u00e0 c\u1eb7p b\u00f3ng c\u1ee7a nhau.<\/span><\/li>\n<\/ul>\n
K\u00e9p l\u1ec7ch g\u1ed3m c\u00e1c s\u1ed1 n\u00e0o?<\/em><\/strong><\/span><\/h3>\n\u0110\u00e2y l\u00e0 c\u00e1c s\u1ed1 b\u00f3ng c\u1ee7a k\u00e9p b\u1eb1ng. \u0110\u01a1n gi\u1ea3n h\u01a1n n\u00f3 l\u00e0 s\u1ed1 g\u1ed3m 2 ch\u1eef s\u1ed1 l\u00e0 b\u00f3ng c\u1ee7a nhau. Ch\u1eb3ng h\u1ea1n, k\u00e9p l\u1ec7ch 05 l\u00e0 b\u00f3ng c\u1ee7a k\u00e9p b\u1eb1ng 00, k\u00e9p 16 l\u00e0 b\u00f3ng c\u1ee7a k\u00e9p b\u1eb1ng 11, \u2026 l\u1ec7ch 94 l\u00e0 b\u00f3ng c\u1ee7a k\u00e9p b\u1eb1ng 99. V\u1eady, ta c\u00f3 t\u1ea5t c\u1ea3 l\u00e0 10 b\u1ed9 k\u00e9p t\u01b0\u01a1ng \u1ee9ng v\u1edbi 10 b\u1ed9 k\u00e9p b\u1eb1ng, g\u1ed3m: 05 \u2013 50 \u2013 16 \u2013 61 \u2013 27 \u2013 72 \u2013 38 \u2013 83 \u2013 49 \u2013 94.<\/span><\/p>\n\n