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数学7上有理数大题：模仿举例，套用例子解题方法解决这类求和
（2018·全国初一课时练习）阅读下列例题： 计算：2＋22＋23＋24＋25＋26＋…＋210. 解：设S＝2＋22＋23＋24＋25＋26＋…＋210，① 那么2S＝2×(2＋22＋23＋24＋25＋…＋210)＝22＋23＋24＋25＋…＋210＋211.② ②－①，得
七年级整式规律专题合辑11/34
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