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有关分数的应用题主要研究的就是数量之间的份数关系。解答这类问题,关键是弄清“谁”与“谁”比。【例1】铁球加温后体积增了1/(10),然后温度下降,体积还原。问体积减少了几分之几?【分析与解】一定有同学会说体积还原,体积当然减少了1/(10)。请同学们想一想,是这样的吗?设原来铁球体积为1,则升温后体积为1+1/(10)=(11)/(10)。降温后,体积还原为1,加温后体积为1÷(11)/(10)=(10)/(11),因此体积是减少了1-(10)/(11)=1/(11)。还可以这样分析:把铁球原来的体
The main application of the question on the score is the number of copies between the relationship. The key to answering this kind of question is figuring out who “who” and “who” are. 【Example 1】 After the iron ball heated up by 1 / (10), then the temperature dropped, the volume reduction. Asked the volume reduced by a few? [Analysis and Settlement] Some students will say that volume reduction, of course, reduced the volume of 1 / (10). Would you please think about it, is it like this? Suppose the volume of iron ball is 1, the volume after heating is 1 + 1 / (10) = (11) / (10). After cooling down, the volume is reduced to 1 and the volume after heating is 1 ÷ (11) / (10) = (10) / (11) ). You can also analyze: the original iron body