{"id":17868,"date":"2024-03-17T21:09:01","date_gmt":"2024-03-17T21:09:01","guid":{"rendered":"https:\/\/soicau5106.minhngocxoso.com\/?p=17868"},"modified":"2024-03-17T21:09:01","modified_gmt":"2024-03-17T21:09:01","slug":"so-chan-la-gi-cach-su-dung-so-chan-so-le-trong-lo-de","status":"publish","type":"post","link":"https:\/\/caulobachthu.com\/so-chan-la-gi-cach-su-dung-so-chan-so-le-trong-lo-de\/","title":{"rendered":"s\u1ed1 ch\u1eb5n l\u00e0 g\u00ec? c\u00e1ch s\u1eed d\u1ee5ng s\u1ed1 ch\u1eb5n s\u1ed1 l\u1ebb trong l\u00f4 \u0111\u1ec1"},"content":{"rendered":"\n
B\u1ea1n c\u00f3 bi\u1ebft s\u1ed1 ch\u1eb5n l\u00e0 g\u00ec kh\u00f4ng? M\u1ed9t trong nh\u1eefng ph\u01b0\u01a1ng ph\u00e1p \u0111\u1ec3 t\u00ecm ra con s\u1ed1 may m\u1eafn khi ch\u01a1i l\u00f4 \u0111\u1ec1 \u0111\u01b0\u1ee3c nhi\u1ec1u ng\u01b0\u1eddi \u00e1p d\u1ee5ng hi\u1ec7n nay \u0111\u00f3 ch\u00ednh l\u00e0 \u1ee9ng d\u1ee5ng s\u1ed1 ch\u1eb5n s\u1ed1 l\u1ebb v\u00e0o t\u00ednh \u0111\u1ec1 (c\u00e1ch soi c\u1ea7u ch\u1eb5n l\u1ebb). \u0110\u1ec3 \u00e1p d\u1ee5ng c\u00e1ch n\u00e0y b\u1ea1n c\u1ea7n ph\u1ea3i t\u00ecm hi\u1ec3u c\u00e1ch ch\u01a1i hi\u1ec7u qu\u1ea3 nh\u1ea5t. B\u00e0i vi\u1ebft d\u01b0\u1edbi \u0111\u00e2y s\u1ebd gi\u00fap b\u1ea1n c\u00f3 \u0111\u01b0\u1ee3c nh\u1eefng th\u00f4ng tin b\u1ed5 \u00edch nh\u1ea5t.<\/p>\n\n\n\n
S\u1ed1 ch\u1eb5n l\u00e0 nh\u1eefng con s\u1ed1 c\u00f3 \u0111u\u00f4i sau c\u00f9ng l\u00e0 0, 2, 4, 6, 8 v\u00e0 c\u00f3 th\u1ec3 chia h\u1ebft cho 2. V\u00ed d\u1ee5: 2 chia 2 = 1, 24 chia 2 = 12.<\/p>\n\n\n\n
Trong x\u1ed5 s\u1ed1 v\u1edbi 100 con s\u1ed1 t\u1eeb 00 – 99 th\u00ec s\u1ed1 ch\u1eb5n chi\u1ebfm 50%, g\u1ed3m: 00, 02, 04, 06, 08, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98.<\/p>\n\n\n\n
S\u1ed1 0 l\u00e0 ch\u1eb5n hay l\u1ebb s\u1ebd \u0111\u01b0\u1ee3c x\u00e9t tr\u00ean nh\u1eefng y\u1ebfu t\u1ed1 sau \u0111\u00e2y:<\/p>\n\n\n\n
M\u1ed9t s\u1ed1 n \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 \u201cs\u1ed1 ch\u1eb5n\u201d n\u1ebfu s\u1ed1 \u0111\u00f3 c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c bi\u1ec3u di\u1ec5n b\u1eb1ng c\u00f4ng th\u1ee9c n = i x 2 v\u1edbi i l\u00e0 m\u1ed9t s\u1ed1 nguy\u00ean b\u1ea5t k\u1ef3.<\/p>\n\n\n\n
V\u00ed; d\u1ee5, 10 l\u00e0 s\u1ed1 ch\u1eb5n b\u1edfi 10 c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c ph\u00e2n t\u00edch ra th\u00e0nh 10 = 5 x 2, v\u1edbi 5 l\u00e0 m\u1ed9t s\u1ed1 nguy\u00ean. C\u00f2n s\u1ed1 0 th\u00ec b\u1eb1ng 0 x 2 = 0, v\u1eady n\u00ean 0 ph\u1ea3i l\u00e0 s\u1ed1 ch\u1eb5n.<\/p>\n\n\n\n
S\u1ed1 ch\u1eb5n chia h\u1ebft cho 2, s\u1ed1 l\u1ebb chia cho 2 s\u1ebd d\u01b0 1. V\u00ed; d\u1ee5 nh\u01b0 5 l\u00e0 s\u1ed1 l\u1ebb v\u00ec chia cho 2 s\u1ebd d\u01b0 1. T\u01b0\u01a1ng t\u1ef1, 4 l\u00e0 s\u1ed1 ch\u1eb5n v\u00ec chia h\u1ebft \u0111\u01b0\u1ee3c cho 2.<\/p>\n\n\n\n
X\u00e9t tr\u00ean kh\u00e1i ni\u1ec7m n\u00e0y, 0 chia 2 c\u0169ng b\u1eb1ng 0, v\u1eady k\u1ebft lu\u1eadn 0 l\u00e0 s\u1ed1 ch\u1eb5n.<\/p>\n\n\n\n
N\u1ebfu h\u1ecdc gi\u1ecfi to\u00e1n, c\u00f3 l\u1ebd b\u1ea1n \u0111\u00e3 qu\u00e1 quen thu\u1ed9c v\u1edbi ph\u01b0\u01a1ng ph\u00e1p ch\u1ee9ng minh kinh \u0111i\u1ec3n n\u00e0y r\u1ed3i. Hi\u1ec3u n\u00f4m na, \u0111\u00e2y l\u00e0 ph\u01b0\u01a1ng ph\u00e1p ch\u1ee9ng minh “ng\u01b0\u1ee3c”, \u0111i t\u1eeb gi\u1ea3 thi\u1ebft sai \u0111\u1ec3 ch\u1ee9ng minh gi\u1ea3 thi\u1ebft ng\u01b0\u1ee3c l\u1ea1i l\u00e0 \u0111\u00fang.<\/p>\n\n\n\n
Gi\u1ea3 s\u1eed 0 l\u00e0 m\u1ed9t s\u1ed1 l\u1ebb, m\u00e0 ch\u00fang ta \u0111\u1ec1u bi\u1ebft m\u1ecdi s\u1ed1 l\u1ebb n \u0111\u1ec1u \u0111\u01b0\u1ee3c bi\u1ec3u di\u1ec5n \u1edf d\u1ea1ng n = 2k + 1 v\u1edbi k l\u00e0 m\u1ed9t s\u1ed1 nguy\u00ean b\u1ea5t k\u1ef3.<\/p>\n\n\n\n
Tuy nhi\u00ean khi x\u00e9t n = 0, b\u00e0i to\u00e1n n\u00e0y cho ra k\u1ebft qu\u1ea3 l\u00e0 k = -0,5, t\u1ee9c kh\u00f4ng ph\u1ea3i s\u1ed1 nguy\u00ean. \u0110i\u1ec1u n\u00e0y c\u00f3 ngh\u0129a s\u1ed1 0 kh\u00f4ng ph\u1ea3i l\u00e0 s\u1ed1 l\u1ebb, m\u00e0 kh\u00f4ng ph\u1ea3i l\u1ebb th\u00ec ch\u1ec9 c\u00f3 ch\u1eb5n th\u00f4i \u0111\u00fang kh\u00f4ng?<\/p>\n\n\n\n
\u0110\u1ec3 \u1ee9ng d\u1ee5ng s\u1ed1 ch\u1eb5n l\u1ebb v\u00e0o t\u00ednh \u0111\u1ec1 c\u00e1c b\u1ea1n c\u1ea7n ph\u1ea3i n\u1eafm \u0111\u01b0\u1ee3c nh\u1eefng c\u00e1ch ch\u01a1i hi\u1ec7u qu\u1ea3. D\u01b0\u1edbi \u0111\u00e2y l\u00e0 m\u1ed9t s\u1ed1 g\u1ee3i \u00fd b\u1ea1n c\u00f3 th\u1ec3 tham kh\u1ea3o:<\/p>\n\n\n\n
D\u1ef1a v\u00e0o t\u1ea7n su\u1ea5t loto gi\u1ea3i \u0111\u1eb7c bi\u1ec7t c\u00e1c b\u1ea1n s\u1ebd th\u1ea5y \u0111\u01b0\u1ee3c con s\u1ed1 may m\u1eafn. C\u00e1c d\u1ea1ng ch\u1eb5n l\u1ebb th\u01b0\u1eddng kh\u00f4ng ra 4 ng\u00e0y li\u00ean t\u1ee5c. N\u1ebfu anh em th\u1ea5y m\u1ed9t d\u1ea1ng \u0111\u1ec1 ch\u1eb5n l\u1ebb n\u00e0o \u0111\u00e3 ra 3 ng\u00e0y li\u00ean ti\u1ebfp th\u00ec c\u00e1c b\u1ea1n s\u1ebd lo\u1ea1i \u0111i 25 s\u1ed1 c\u1ee7a d\u1ea1ng \u0111\u00f3 \u0111\u1ec3 ch\u01a1i.<\/p>\n\n\n\n