0-9任意两个数字组成的两位数组合有多少组？ 0到9十位数组成两位数的组合最多能组成多少组合，分别有那些
\u4e24\u4f4d\u65700-9\u53ef\u7ec4\u6210\u4e24\u4f4d\u5bc6\u7801\u591a\u5c11\u7ec4100\u7ec4\u3002
\u7b2c\u4e00\u4f4d\u6570\u670910\u79cd\u9009\u62e9\uff1b\u7b2c\u4e8c\u4f4d\u6570\u4e5f\u670910\u79cd\u9009\u62e9\u3002\u7531\u4e58\u6cd5\u5b9a\u7406\u77e5\uff1a10*10=100\uff0c\u5373\u6709100\u7ec4\u3002
\u6392\u5217\uff1a\u4ecen\u4e2a\u4e0d\u540c\u5143\u7d20\u4e2d\uff0c\u4efb\u53d6m(m\u2264n,m\u4e0en\u5747\u4e3a\u81ea\u7136\u6570,\u4e0b\u540c\uff09\u4e2a\u5143\u7d20\u6309\u7167\u4e00\u5b9a\u7684\u987a\u5e8f\u6392\u6210\u4e00\u5217\uff0c\u53eb\u505a\u4ecen\u4e2a\u4e0d\u540c\u5143\u7d20\u4e2d\u53d6\u51fam\u4e2a\u5143\u7d20\u7684\u4e00\u4e2a\u6392\u5217\uff1b\u4ecen\u4e2a\u4e0d\u540c\u5143\u7d20\u4e2d\u53d6\u51fam(m\u2264n\uff09\u4e2a\u5143\u7d20\u7684\u6240\u6709\u6392\u5217\u7684\u4e2a\u6570\uff0c\u53eb\u505a\u4ecen\u4e2a\u4e0d\u540c\u5143\u7d20\u4e2d\u53d6\u51fam\u4e2a\u5143\u7d20\u7684\u6392\u5217\u6570\uff0c\u7528\u7b26\u53f7 A(n,m\uff09\u8868\u793a\u3002
\u8ba1\u7b97\u516c\u5f0f\uff1a
\u6269\u5c55\u8d44\u6599\uff1a
\u4e58\u6cd5\u539f\u7406\u548c\u5206\u6b65\u8ba1\u6570\u6cd5
1\u3001\u4e58\u6cd5\u539f\u7406\uff1a\u505a\u4e00\u4ef6\u4e8b\uff0c\u5b8c\u6210\u5b83\u9700\u8981\u5206\u6210n\u4e2a\u6b65\u9aa4\uff0c\u505a\u7b2c\u4e00\u6b65\u6709m1\u79cd\u4e0d\u540c\u7684\u65b9\u6cd5\uff0c\u505a\u7b2c\u4e8c\u6b65\u6709m2\u79cd\u4e0d\u540c\u7684\u65b9\u6cd5\uff0c\u2026\u2026\uff0c\u505a\u7b2cn\u6b65\u6709mn\u79cd\u4e0d\u540c\u7684\u65b9\u6cd5\uff0c\u90a3\u4e48\u5b8c\u6210\u8fd9\u4ef6\u4e8b\u5171\u6709N=m1\u00d7m2\u00d7m3\u00d7\u2026\u00d7mn\u79cd\u4e0d\u540c\u7684\u65b9\u6cd5\u3002
2\u3001\u5408\u7406\u5206\u6b65\u7684\u8981\u6c42
\u4efb\u4f55\u4e00\u6b65\u7684\u4e00\u79cd\u65b9\u6cd5\u90fd\u4e0d\u80fd\u5b8c\u6210\u6b64\u4efb\u52a1\uff0c\u5fc5\u987b\u4e14\u53ea\u987b\u8fde\u7eed\u5b8c\u6210\u8fd9n\u6b65\u624d\u80fd\u5b8c\u6210\u6b64\u4efb\u52a1\uff1b\u5404\u6b65\u8ba1\u6570\u76f8\u4e92\u72ec\u7acb\uff1b\u53ea\u8981\u6709\u4e00\u6b65\u4e2d\u6240\u91c7\u53d6\u7684\u65b9\u6cd5\u4e0d\u540c\uff0c\u5219\u5bf9\u5e94\u7684\u5b8c\u6210\u6b64\u4e8b\u7684\u65b9\u6cd5\u4e5f\u4e0d\u540c\u3002
3\u3001\u4e0e\u540e\u6765\u7684\u79bb\u6563\u578b\u968f\u673a\u53d8\u91cf\u4e5f\u6709\u5bc6\u5207\u76f8\u5173\u3002
90\u3002\u5206\u522b\u4e3a10\uff0c11\uff0c12\u2026\u2026..97\uff0c98\uff0c99\u3002
\u5341\u4f4d\u6570\u4e0d\u80fd\u4e3a0\uff0c\u6545\u67099\u79cd\u9009\u62e9\uff0c\u4e2a\u4f4d\u6570\u53ef\u4ee5\u4e3a0\uff0c\u6545\u670910\u79cd\u9009\u62e9\uff0c\u7531\u4e58\u6cd5\u5b9a\u7406\u5f97\uff1a9*10=90\uff0c\u6545\u670990\u79cd\u9009\u62e9\u3002
\u4ecen\u4e2a\u4e0d\u540c\u5143\u7d20\u4e2d\uff0c\u4efb\u53d6m(m\u2264n,m\u4e0en\u5747\u4e3a\u81ea\u7136\u6570,\u4e0b\u540c\uff09\u4e2a\u5143\u7d20\u6309\u7167\u4e00\u5b9a\u7684\u987a\u5e8f\u6392\u6210\u4e00\u5217\uff0c\u53eb\u505a\u4ecen\u4e2a\u4e0d\u540c\u5143\u7d20\u4e2d\u53d6\u51fam\u4e2a\u5143\u7d20\u7684\u4e00\u4e2a\u6392\u5217\uff1b\u4ecen\u4e2a\u4e0d\u540c\u5143\u7d20\u4e2d\u53d6\u51fam(m\u2264n\uff09\u4e2a\u5143\u7d20\u7684\u6240\u6709\u6392\u5217\u7684\u4e2a\u6570\uff0c\u53eb\u505a\u4ecen\u4e2a\u4e0d\u540c\u5143\u7d20\u4e2d\u53d6\u51fam\u4e2a\u5143\u7d20\u7684\u6392\u5217\u6570\uff0c\u7528\u7b26\u53f7 A(n,m\uff09\u8868\u793a\u3002
\u8ba1\u7b97\u516c\u5f0f\uff1a
\u6b64\u5916\u89c4\u5b9a0!=1(n!\u8868\u793an(n-1)(n-2)...1,\u4e5f\u5c31\u662f6\uff01=6x5x4x3x2x1
\u6269\u5c55\u8d44\u6599\uff1a
\u4e00\u3001\u6392\u5217\uff1aA(n,m)=n\u00d7\uff08n-1\uff09.\uff08n-m+1\uff09=n!/\uff08n-m\uff09!(n\u4e3a\u4e0b\u6807,m\u4e3a\u4e0a\u6807,\u4ee5\u4e0b\u540c)
\u4e8c\u3001\u7ec4\u5408\uff1aC(n,m)=P(n,m)/P(m,m) =n!/m!\uff08n-m\uff09!\uff1b\u4f8b\u5982\uff1aA(4,2)=4!/2!=4*3=12\uff1bC(4,2)=4!/(2!*2!)=4*3/(2*1)=6
\u4e09\u3001\u4e58\u6cd5\u539f\u7406\u548c\u5206\u6b65\u8ba1\u6570\u6cd5
1\u3001\u4e58\u6cd5\u539f\u7406\uff1a\u505a\u4e00\u4ef6\u4e8b\uff0c\u5b8c\u6210\u5b83\u9700\u8981\u5206\u6210n\u4e2a\u6b65\u9aa4\uff0c\u505a\u7b2c\u4e00\u6b65\u6709m1\u79cd\u4e0d\u540c\u7684\u65b9\u6cd5\uff0c\u505a\u7b2c\u4e8c\u6b65\u6709m2\u79cd\u4e0d\u540c\u7684\u65b9\u6cd5\uff0c\u2026\u2026\uff0c\u505a\u7b2cn\u6b65\u6709mn\u79cd\u4e0d\u540c\u7684\u65b9\u6cd5\uff0c\u90a3\u4e48\u5b8c\u6210\u8fd9\u4ef6\u4e8b\u5171\u6709N=m1\u00d7m2\u00d7m3\u00d7\u2026\u00d7mn\u79cd\u4e0d\u540c\u7684\u65b9\u6cd5\u3002
2\u3001\u5408\u7406\u5206\u6b65\u7684\u8981\u6c42\uff1a\u4efb\u4f55\u4e00\u6b65\u7684\u4e00\u79cd\u65b9\u6cd5\u90fd\u4e0d\u80fd\u5b8c\u6210\u6b64\u4efb\u52a1\uff0c\u5fc5\u987b\u4e14\u53ea\u987b\u8fde\u7eed\u5b8c\u6210\u8fd9n\u6b65\u624d\u80fd\u5b8c\u6210\u6b64\u4efb\u52a1\uff1b\u5404\u6b65\u8ba1\u6570\u76f8\u4e92\u72ec\u7acb\uff1b\u53ea\u8981\u6709\u4e00\u6b65\u4e2d\u6240\u91c7\u53d6\u7684\u65b9\u6cd5\u4e0d\u540c\uff0c\u5219\u5bf9\u5e94\u7684\u5b8c\u6210\u6b64\u4e8b\u7684\u65b9\u6cd5\u4e5f\u4e0d\u540c\u3002
十位只能是1到9，个位你0到9，9*10=90所以是90 个
90个
绛旓細涓や釜鏁板瓧缁勬垚鐨勪袱浣嶆暟,濡傛灉鍙互鐩稿悓鐨勶紙濡11銆22绛夛級鏈9*10=90缁,濡傛灉涓嶈兘鐩稿悓鐨,鏄90-9=81缁
绛旓細67,68,69,70,71,
绛旓細9脳9=81锛鏁板瓧涓嶅彲閲嶅锛10~99 闄ゅ幓11銆22銆33鈥︹99
绛旓細0鍒9涓换鎰忎袱涓暟瀛楃粍鎴愮殑鏈澶т袱浣嶆暟鏄98锛屾渶灏忎袱浣嶆暟鏄10锛屽畠浠殑宸槸88銆
绛旓細1-9鏁板瓧浠诲彇2涓粍鎴2浣嶆暟鐨勬帓鍒楁槸9*9=81涓斿彇鐨勪袱涓暟鐩稿悓鏃剁殑鍙兘鏈9娆 1-9鍜0缁勬垚涓や綅鏁扮殑鎯呭喌鍙湁9娆.鎵浠0-9浠诲彇2涓粍鎴2浣嶆暟鐨勬満浼氬氨鏄81-9+9=81
绛旓細涓嶈兘閲嶅鐨勮瘽锛岀瓟妗堟槸81绉嶃傝В鏋愶細涓や綅鏁10-99锛屾湰鏉ュ氨鍙湁90涓紝鐜板湪鍑忓幓閲嶅鐨11 22...99锛屼竴鍏9涓锛岃繕鍓81涓紱涔熷彲浠ョ敤鎺掑垪缁勫悎鏉ヨВ绛旇棰橈細鍗佷綅涓婏紝鍙兘閫1-9锛9绉嶏紱涓綅涓婏紝鑳介0-9锛10绉嶏紝浣嗘槸涓嶈兘涓庡崄浣嶇殑閲嶅锛屾墍浠-1锛屼篃鏄9绉嶏紝寰楀埌鍏紡锛9*9=81绉嶃傚姞娉曞師鐞嗗拰鍒嗙被璁℃暟娉 1...
绛旓細鑻ユ槸涓や綅灏忔暟锛屾渶澶х殑鏄8.9锛屾渶灏忕殑鏄0.1銆
绛旓細鍦0鍒9杩欏崄涓暟瀛涓紝鍗佷綅鏁伴櫎0澶栵紝鍙互鏈9绉嶉夋嫨銆備釜浣嶆暟鍙互鍦ㄤ綑涓嬬殑9涓暟涓浠绘剰閫夋嫨銆傛墍浠ワ紝9脳9锛81 绛旀锛氬彲浠缁勬垚81涓病鏈夐噸澶嶆暟瀛鐨勪袱浣嶆暟銆
绛旓細涓や綅鏁版槸鎸囦竴涓暟鐢涓や釜鏁板瓧缁勬垚锛屽叾涓涓涓暟瀛楀彲浠ユ槸浠1鍒9鐨勪换鎰忔暟瀛锛岃岀浜屼釜鏁板瓧鍙互鏄粠0鍒9鐨勪换鎰忔暟瀛椼傚洜姝わ紝涓や綅鏁扮殑缁勫悎鑼冨洿浠10鍒99銆傚湪杩欎釜鑼冨洿鍐咃紝99鏄渶澶鐨勪袱浣嶆暟銆99鏄敱涓や釜鐩稿悓鐨鏁板瓧9缁勬垚鐨锛岃〃绀轰節鍗佷節銆傚湪闃挎媺浼暟瀛楃郴缁熶腑锛屾瘡涓浣嶆暟瀛楃殑浣嶇疆琛ㄧず涓嶅悓鐨勬暟浣嶏紝浠庡彸鍒板乏...
绛旓細10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,...
