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初中必考！带点循环小数转化分数的3种实用技巧
锛堟媿妗屽瓙锛夊搸锛佺湅鍒拌€冨嵎涓?.4虈5虈杩欑澶撮《甯︾偣鐨勬暟灏辨墜鎶栵紵鍒厡锛佸綋骞存垜鍟冪潃骞茶剢闈㈢爺绌跺嚭鐨勮繖涓夋嫑锛屼繚浣犳瘮鍚冩场闈㈣繕绠€鍗曘€備笂涓湀闅斿鐝€佺帇鐢ㄨ繖鏂规硶锛屽崟鍏冭€冪洿鎺ュ鎹炰簡8鍒嗭紒
馃幆 鎶€宸т竴锛氫竾鑳?璁惧厓娑堟秷涔?锛堥€傜敤鎵€鏈夌被鍨嬶級
鈥?strong>鈥嬪満鏅繕鍘熲€?/strong>鈥嬶細纰板埌0.727272...杩欑绾惊鐜皬鏁?br/> 鈥?strong>鈥嬪彛璇€鈥?/strong>鈥嬶細璁炬湭鐭ユ暟鈫掓壘鍊嶆暟鈫掔浉鍑忔秷寰幆鈫掔害鍒嗘敹宸?/p>
- 璁緓=0.72虈 鈫?澶撮《涓や釜鐐硅鏄庡惊鐜妭鏄袱浣嶆暟
- 涔?00锛?00x=72.727272...锛堝皬鏁扮偣鍙崇Щ涓や綅锛?/li>
- 鐜╂秷娑堜箰锛?00x - x =72.727272... -0.727272...
鈫?br/> 99x=72 鈫?x=72/99=鈥?strong>鈥?/11鈥?/strong>鈥嬶紙鍒嗗瓙鍒嗘瘝閮矫?锛?/li>
锛堟暡榛戞澘锛夆€?strong>鈥嬪繀鏉€鍏紡鈥?/strong>鈥嬶細寰幆鑺傚嚑浣嶅氨涔?0鐨勫嚑娆℃柟锛佺函寰幆灏忔暟=寰幆鑺?(10鈦?1)
馃З 鎶€宸т簩锛氭贩琛€鍎挎媶鍒嗘湳锛堜笓娌?.58333...杩欑被娣峰惊鐜級
鈥?strong>鈥嬪疄鎴樻紨缁冣€?/strong>鈥嬶細鎶?.58虈3虈鎷嗘垚"鍥哄畾+寰幆"涓ゅ潹
馃憠 鍏堟媶鎴?.58+0.00333...
| 閮ㄥ垎 | 澶勭悊鏂规硶 | 缁撴灉 |
|---|---|---|
| 0.58 | 鐩存帴鍐?8/100 | 29/50 |
| 0.00333... | 璁緔=0.00333...鈫掍箻10鈫掔浉鍑?/td> | y=1/300 |
鈥?strong>鈥嬪悎鎴愮粷鎷涒€?/strong>鈥嬶細29/50 +1/300 = (174+1)/300 = 鈥?strong>鈥?75/300=7/12鈥?/strong>鈥?/p>
锛堟媿澶ц吙锛夎浣忎簡锛佹贩寰幆杞寲灏变笁姝ワ細
鈶犳媶鍥哄畾閮ㄥ垎 鈶″鐞嗙函寰幆 鈶㈤€氬垎鍚堝苟
馃搶 鎶€宸т笁锛氶槻鍧戞寚鍗?楠岃瘉绁炲櫒
鈥?strong>鈥嬫柊鎵嬪繀鐪嬪姣旇〃鈥?/strong>鈥嬶細
| 鎯呭喌 | 姝ｇ‘鎿嶄綔 | 浣滄鎿嶄綔 |
|---|---|---|
| 0.1234234234... | 寰幆鑺傛槸234锛堢湅杩炵画閲嶅鐨勬渶闀挎锛?/td> | 璇寰幆鑺傛槸34 |
| 缁撴灉妫€楠?/td> | 7/11=0.636363...锛堟寜璁＄畻鍣ㄧ‘璁わ級 | 鎳掑緱楠岃瘉瀵艰嚧鑰冭瘯姝ラ鍒嗗叏鎵?/td> |
| 甯︾偣鏍囪 | 鐐瑰湪寰幆鑺傞灏炬暟瀛楀ご椤?/td> | 鐐瑰湪涓鏁板瓧涓婏紙鐩存帴鍒ら敊锛侊級 |
鈥?strong>鈥嬬嫭瀹堕獙璇佹硶鈥?/strong>鈥嬶細
- 鍒嗘暟杞洖灏忔暟鐪嬫槸鍚︿竴鑷达紙姣斿7/12鈮?.583333...锛?/li>
- 鐢ㄥ垎瀛惷峰垎姣嶆椂锛岃绠楀櫒鏄剧ず寰幆鑺傚氨瀵逛簡
馃挕 鑰佸徃鏈虹纰庡康锛堣€冨満瀹炴垬缁忛獙锛?/h3>
涓婂懆鐩戣€冪湅鍒颁釜鐙犱汉锛?鍒嗛挓鍋氬畬涓夐亾寰幆灏忔暟棰樸€傚悗鏉ヤ竴闂墠鐭ラ亾锛屼汉瀹舵棭鎶娾€?strong>鈥嬪父瑙佸惊鐜妭鍒嗘暟鈥?/strong>鈥嬭儗鐔熶簡锛?/p>
- 0.6虈 = 2/3
- 0.8虈3虈 = 5/6
- 0.1虈4虈2虈8虈5虈7虈 = 1/7锛堣繖涓秴鍙樻€侊紒锛?/li>
涓嶈繃璇村疄鍦ㄧ殑锛屾璁扮‖鑳屼笉濡傛帉鎻℃柟娉曘€傚氨鍍忛獞鑷杞︼紝浼氬钩琛′簡鎹㈠暐杞﹂兘鑳介獞銆備笅娆¤€冨墠娉￠潰鏃堕棿锛屼笉濡傛嬁鏍圭伀鑵胯偁褰撳皬鏁扮偣锛屽湪鍖呰绾镐笂鍒掓媺涓や笅锛屼繚鍑嗘瘮姝荤璇炬湰绠＄敤锛?/p>
锛堢獊鐒跺帇浣庡０闊筹級鏈€鍚庨€忛湶涓槄鍗疯€佸笀鎵嶇煡閬撶殑绉樺瘑锛氣€?strong>鈥嬭繃绋嬪垎鍗?0%鈥?/strong>鈥嬶紒鍝€曟渶鍚庣粨鏋滅畻閿欎簡锛岃鍏冦€佹秷寰幆杩欎簺姝ラ鍐欏叏浜嗭紝鐓ф牱鑳芥嬁涓€澶у崐鍒嗐€傛墍浠ュ晩锛屾柟娉曟瘮绛旀鏇撮噸瑕侊紒