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,
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,
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,
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,
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,
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,
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,
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.
分析:判斷一個(gè)分?jǐn)?shù)能否化成有限小數(shù),首先要看這個(gè)分?jǐn)?shù)是不是最簡分?jǐn)?shù),如果不是最簡分?jǐn)?shù)要進(jìn)行約分,再看約分后的最簡分?jǐn)?shù),如果分母中只含有質(zhì)因數(shù)2或5,這個(gè)分?jǐn)?shù)就能化成有限小數(shù);如果分母中含有2或5以外的質(zhì)因數(shù),這個(gè)分?jǐn)?shù)就不能化成有限小數(shù).
解答:
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的分母中只含有質(zhì)因數(shù)2和5,
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的分母中只含有質(zhì)因數(shù)2和5,
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的分母中只有質(zhì)因數(shù)5,
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的分母中只含有質(zhì)因數(shù)2和5,
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的分母中只有質(zhì)因數(shù)2,
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化簡后是
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,分母中只有質(zhì)因數(shù)2,
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化簡后是
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,分母中只有質(zhì)因數(shù)2,
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化簡后是
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,分母中只有質(zhì)因數(shù)5,
這些都能化成有限小數(shù);
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的分母中含有質(zhì)因數(shù)3,不能化成有限小數(shù).
故答案為:
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,
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,
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,
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,
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,
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,
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,
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.
點(diǎn)評:此題主要考查判斷一個(gè)分?jǐn)?shù)能否化成有限小數(shù)的方法,根據(jù)一個(gè)最簡分?jǐn)?shù),如果分母中只含有質(zhì)因數(shù)2或5,這個(gè)分?jǐn)?shù)就能化成有限小數(shù);如果分母中含有2或5以外的質(zhì)因數(shù),這個(gè)分?jǐn)?shù)就不能化成有限小數(shù).