(1十3十5十7十…十211)一(2十4十6十…十210)怎样巧算 (1十3十5十7十……十2o17)一(2十4十6十8……十2...
(1\u53413\u53415\u53417\u5341\u2026\u2026\u53412005)\u4e00(2\u53414\u53416\u53418\u5341\u2026\u2026\u53412004)\u600e\u505a?\u8fc7\u7a0b2005-1*1002=1003
\u524d\u540e\u4e24\u4e2a\u5206\u4e00\u7ec4
2-1\u662f\u4e00\u7ec4\uff0c4-3\u662f\u4e00\u7ec4\uff0c6-5\u662f\u4e00\u7ec4......2004-2003\u662f\u4e00\u7ec4\uff0c\u56e0\u4e3a\u6bcf\u4e00\u7ec4\u503c\u90fd\u4e3a1\uff0c\u6240\u4ee5\u4e00\u5171\u67092004\u00f72=1002\u7ec4\u3002\u5c31\u662f\u8bf4\u67091001\u4e2a1\u76f8\u52a0
1-2+3-4+5-6\u2026+2001-2002
\uff1d\uff081\uff0d2\uff09\uff0b\uff083\uff0d4\uff09\uff0b\uff085\uff0d6\uff09\uff0b\u2026\u2026\uff0b\uff082003\uff0d2004\uff09
\uff1d\uff08\uff0d1\uff09\uff0b\uff08\uff0d1\uff09\uff0b\uff08\uff0d1\uff09\uff0b\u2026\u2026\uff0b\uff08\uff0d1\uff09
\uff1d\uff08\uff0d1\uff09\u00d71002
\uff1d\uff0d1002
\u7136\u540e\u5c31\u662f2005-1002
=\uff081-2\uff09+\uff083-4\uff09+\uff085-6\uff09+....+\uff082016-2017\uff09
=-1*(2016/2)
=-1008
=1+3+5+7+……+211-2-4-6-……-210
=1-2+3-4+5-……-210+211
=1+(3-2)+(5-4)+……+(211-210) 共105组
=1+105
=106
(1十3十5十7十…十211)一(2十4十6十…十210)
=1+（3-2）+（5-4）+（7-6）+……+（209-208）+（211-210）
=1+1+1+1……+1+1
=1+210/2
=1+105
=106
用数列求和公式
绛旓細(1鍗3鍗5鍗7鍗佲﹀崄211)涓(2鍗4鍗6鍗佲﹀崄210)=1+3+5+7+鈥︹+211-2-4-6-鈥︹-210 =1-2+3-4+5-鈥︹-210+211 =1+(3-2)+(5-4)+鈥︹+(211-210) 鍏105缁 =1+105 =106
绛旓細1-2+3-4+5-6...-210+211=锛1+211)脳211梅2=22366棣栭」鍔犳湯椤逛箻浠ラ」鏁伴櫎浠ヤ簩
绛旓細1鍗3鍗5鍗7鍗... 鍗21浜(11)x(11)
绛旓細锛1鍗3鍗5鍗佲﹀崄2021锛変竴锛2020鍗2018鍗2016鍗佲﹀崄2锛=锛2021涓2020锛夊崄锛2019涓2018锛夊崄锛2017涓2016锛夊崄鈥+锛3涓2锛夊崄1 =1010脳1鍗1 =1011
绛旓細瀵
绛旓細1+3+5+7+9+11 锛3+7+锛11+9锛+5+1 锛10+20+6 锛36
绛旓細1鍗3鍗5鍗7...鍗29鍜屾槸濂囨暟锛屼竴鍏辨槸15涓鏁扮殑鍜岋紝鏄鏁般
绛旓細1鍗3鍗5鍗7鍗佲︹﹀崄2019 =(1+2019銆+(3+2017)+(5+2015)+ (7+2013)+鈥︹+(1009+1011)=2020+2020+鈥︹2020 =2020脳505 =1020100
绛旓細(1鍗3鍗5鍗7鍗銆傘傘傚崄2017)涓(2鍗4鍗6鍗8涓2016)=1+2016/2 =1+1008 =1009 璋㈣阿锛岃閲囩撼
绛旓細(1+21)脳11梅2=121
