求教奥数题:从1234567891011121314。。。。。。4950这个多位数中,划去80个数字,使剩下的数字
\u6c42\u6570\u5b66\u9898\u4e03\u5e74\u7ea780\u9053\u8131\u5f0f\u8ba1\u7b97\u3002
408\uff0d12\u00d724 \uff0846\uff0b28\uff09\u00d760 42\u00d750\uff0d1715\u00f75
32\uff0b105\u00f75 \uff08108\uff0b47\uff09\u00d752 420\u00d7\uff08327\uff0d238\uff09
(4121+2389)\u00f77 671\u00d715-974 469\u00d712+1492
405\u00d7(3213-3189) 5000-56\u00d723 125\u00d7(97-81)
6942+480\u00f73 304\u00d732-154 20+80\u00f74-20\uff1d
100\u00f7\uff0832-30\uff09\u00d70\uff1d 25\u00d74-12\u00d75\uff1d
70\u00d7\u3014\uff0842-42\uff09\u00f718\u3015\uff1d 75\u00d765+75\u00d735\uff1d
\u7528\u7b80\u4fbf\u65b9\u6cd5\u8ba1\u7b97\u4e0b\u9762\u5404\u9898
1\u300189+124+11+26+48 2\u3001875-147-23
3\uff0e25\u00d7125\u00d740\u00d78 4\u3001147\u00d78+8\u00d753
5\u3001125\u00d764 6\u30010.9\uff0b1.08\uff0b0.92\uff0b0.1
\u7528\u7b80\u4fbf\u65b9\u6cd5\u8ba1\u7b97
\u246089+124+11+26+48 \u2461875-147-23
\u2462147\u00d78+8\u00d753 \u2463125\u00d764
\u8ba1\u7b97\u4e0b\u9762\u5404\u9898\uff0e
1\uff0e280\uff0b840\u00f724\u00d75 2\uff0e85\u00d7(95\uff0d1440\u00f724)
3\uff0e58870\u00f7(105\uff0b20\u00d72) 4\uff0e80400\uff0d(4300\uff0b870\u00f715)
5\uff0e1437\u00d727\uff0b27\u00d7563 6\uff0e81432\u00f7(13\u00d752\uff0b78)
7\uff0e125\u00d7(33\uff0d1) 8\uff0e37.4\uff0d(8.6\uff0b7.24\uff0d6.6)
\u8ba1\u7b97\u3002\uff081\u22361\uff09
\uff081\uff09156\u00d7107-7729 \uff082\uff0937.85-\uff087.85+6.4\uff09
\uff083\uff09287\u00d75+96990\u00f7318 \uff084\uff091554\u00f7[\uff0872-58\uff09\u00d73]
\u8131\u5f0f\u8ba1\u7b97
2800\u00f7 100\uff0b789 \uff08947\uff0d599\uff09\uff0b76\u00d764
1\uff0e36\u00d7(913\uff0d276\u00f723) 2\uff0e(93\uff0b25\u00d721)\u00d79
3\uff0e507\u00f713\u00d763\uff0b498 4\uff0e723\uff0d(521\uff0b504)\u00f725
5\uff0e384\u00f712\uff0b23\u00d7371 6\uff0e(39\uff0d21)\u00d7(396\u00f76)
\uff081\uff09156\u00d7[(17.7-7.2)\u00f73] \uff082\uff09[37.85-\uff087.85+6.4\uff09] \u00d730
\uff083\uff0928\u00d7(5+969.9\u00f7318) \uff084\uff0981\u00f7[\uff0872-54\uff09\u00d79]
57\u00d712\uff0d560\u00f735 848\uff0d640\u00f716\u00d712
960\u00f7\uff081500\uff0d32\u00d745\uff09 [192\uff0d\uff0854\uff0b38\uff09]\u00d767
138\u00d725\u00d74 (13\u00d7125)\u00d7(3\u00d78) (12+24+80)\u00d750 704\u00d725 25\u00d732\u00d7125 32\u00d7(25+125)
178\u00d7101\uff0d178 84\u00d736+64\u00d784 75\u00d799+2\u00d775 83\u00d7102\uff0d83\u00d72 98\u00d7199
123\u00d718\uff0d123\u00d73+85\u00d7123 50\u00d7(34\u00d74)\u00d73 25\u00d7\uff0824+16\uff09 178\u00d799+178
79\u00d742+79+79\u00d757 7300\u00f725\u00f74 8100\u00f74\u00f775 75\u00d727+19\u00d72 5 31\u00d7870+13\u00d7310
4\u00d7(25\u00d765+25\u00d728) 138\u00d725\u00d74 (13\u00d7125)\u00d7(3\u00d78) (12+24+80)\u00d750
25\u00d732\u00d7125 32\u00d7(25+125) 102\u00d776 58\u00d798
178\u00d7101\uff0d178 84\u00d736+64\u00d784 75\u00d799+2\u00d775 83\u00d7102\uff0d83\u00d72
98\u00d7199 123\u00d718\uff0d123\u00d73+85\u00d7123 50\u00d7(34\u00d74)\u00d73 25\u00d7\uff0824+16\uff09
178\u00d799+178 79\u00d742+79+79\u00d757 7300\u00f725\u00f74 8100\u00f74\u00f775
(1\uff09\u8fde\u63a5BC'\uff0cCA'\uff0cAB'
\u25b3ABC'\u548c\u25b3ABC\u7b49\u5e95\u540c\u9ad8
\u6240\u4ee5S\u25b3ABC'=S\u25b3ABC
\u53c8\u56e0\u4e3aS\u25b3ABC'=S\u25b3A'BC'\uff08\u7b49\u5e95\u540c\u9ad8\uff09
\u6240\u4ee5S\u25b3ABC=1/2S\u25b3A'AC'
\u540c\u7406\u53ef\u5f97
S\u25b3ABC=1/2S\u25b3A'BB'
S\u25b3ABC=1/2S\u25b3B'CC'
\u6240\u4ee5S\u25b3ABC=1/7S\u25b3A'B'C'
\uff08\u6216\u25b3A'B'C'=7S\u25b3ABC\uff09
\uff082\uff09\u8fde\u63a5CM
\u56e0\u4e3a\u25b3DEM\u548c\u25b3DCM\u540c\u5e95\u7b49\u9ad8
\u6240\u4ee5S\u25b3DEM=S\u25b3DCM
\u6240\u4ee5S\u25b3BED=S\u25b3BMC
\u53c8\u56e0\u4e3aM\u4e3aAB\u4e2d\u70b9
\u6240\u4ee5S\u25b3BMC=1/2S\u25b3ABC=12
\u5373S\u25b3BED=S\u25b3BMC=12
\uff083\uff09\u8fde\u63a5HD
\u56e0\u4e3aS\u25b3PHD\u4e0e\u77e9\u5f62AMHP\u540c\u5e95\u7b49\u9ad8
\u6240\u4ee5S\u25b3PHD=1/2\u77e9\u5f62AMHP=1/2*7=7/2
\u56e0\u4e3aS\u25b3DHN\u4e0e\u77e9\u5f62HNCQ\u540c\u5e95\u7b49\u9ad8
\u6240\u4ee5S\u25b3DHN=1/2\u77e9\u5f62HQCN=1/2*6=3
\u800cS\u25b3PHN=1/2\u77e9\u5f62BPHN=1/2*4=2\uff08\u7406\u7531\u4e0d\u7528\u6211\u8bf4\u4e86\u5427\uff09
\u6240\u4ee5S\u9634=S\u25b3PHD+S\u25b3DHN+S\u25b3PHN=7/2+3+2=17/2
\uff08\u4e0d\u660e\u767d\u53ef\u4ee5Hi\u6211\u54df\uff09
一共包含:
5个0,6,7,8,9
15个1,2,3,4,
6个5,
划去80个数字,还剩下91-80=11位
是:99995678950
最大的数是99997484950
9、19、29、39的四个9,
47的7,和最后的6个数 484950
最大的数是99997484950
9、19、29、39的四个9,
37的7,和最后的6个数 484950
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绛旓細锛1-2锛壝(3-4)+锛5-6锛-(7-8)=(-1)梅(-1)+(-1)-(-1)=1+(-1)-(-1)=0-(-1)=0+1 =1 锛1-2锛墄(3-4)x锛5-6锛墄(7-8)=(-1)x(-1)x(-1)x(-1)=1x(-1)x(-1)=(-1)x(-1)=1 锛1-2锛墄(3-4)-锛5-6锛+(7-8)=(-1)x(-1)-(-1)+(-1)=1...
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绛旓細8*7*6*5=1680锛屽洜涓鸿兘5678鏁撮櫎鐨勶紝鑲畾鑳借1234鏁撮櫎銆傛墍浠12345678鐨勬渶灏忓叕鍊嶆暟1680 鍚堣鏈1680锛3360锛5040锛6720锛8400锛屽悎璁″氨5涓
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绛旓細鍔犲噺闄ゆ媶濉(楠岀畻)12345678=4 1 +2+3+4+5+6+7+8=36 36-4=3232+2=16 16=8+5+3 1+2-3+4-5+6+7-8=4 2:闈炴爣鍑嗗瀷 鐢ㄤ箻鍙峰悎骞舵暟瀛.12345678=1 12- (3+4- 5-6+7+8) =1 3+4+5+6+7+8=3333-11=2222+2=11 11=5+6 1x7+3+4+9-7+4=20 7+3 +4+9+7+4=3434- ...
绛旓細浣犵殑棰樼洰鍐欓敊浜嗗惂锛屽簲璇ユ槸12345678脳12345678锛12345677脳12345679 瑙o細鍘熷紡锛12345678脳12345678-(12345678-1)脳(12345678+1)锛1
绛旓細涓銆佹瘮濡12345678锛屾垜閫夊彧1234鏄笉琛岀殑锛屽繀椤诲啀鏈変竴涓暟锛屾墠鑳芥弧瓒抽鎰忥紝绛旀鏄簲涓備簩銆佸亣璁炬槸2008涓暟锛屼互姣8涓暟涓哄崟浣嶏紝鍏251缁勬暟锛屾瘡缁勫彇鍓4涓紝鍏1004涓紝鏈鍚庝竴涓2009涔熸弧瓒筹紝鎵浠ユ槸1005涓備笁銆佺敳璺100绫冲姞涓婂仠鐣10绉掑叡闇瑕100/5+10=30绉掞紝涔欒窇100绫冲姞涓婂仠鐣10绉掑叡闇瑕100/4+10=...
绛旓細鍒掑幓12345678 淇濈暀9 8 鍒掑幓1011121314151617181淇濈暀9 19 鍒掑幓2021222324252627282淇濈暀9 19 鍒掑幓303132333435363 淇濈暀73839 15 鍏61 杩欎釜鏁版槸9997383940
绛旓細鍦123456789涓幓鎺12345678,浣跨涓涓暟涓9,鍘绘帀浜8涓暟瀛楀湪10111213141516171819涓,鍘绘帀1011121314151617181,浣跨浜屼釜鏁颁负9,鍘绘帀浜19涓暟瀛,鍏27涓暟瀛楀湪20212223242526272829涓,鍘绘帀2021222324252627282,浣跨涓変釜鏁颁负9,鍘绘帀浜19涓暟瀛,鍏46涓暟瀛楀湪30313233343536373839涓,鍘绘帀3031323334353637383,浣跨鍥涗釜鏁颁负9,鍘绘帀...