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教学百分数应用题,可按下述三个层次由浅入深,由简到繁,循序渐进,步步扎牢。第一屡次:由百分数定义直接引申出三类简单应用题,即①求一个数是另一个数的百分之几;②求一个数的百分之几是多少;③已知某数的百分之几是多少,求某数。用字母式简要地概括一下,就是x%=b÷a,x=a×r%和x=a÷r%(其中x表示所求的数)。(例1)红光农机厂今年第一季度产值是25万元,第二季度产值是40万元。第三季度产值是第一
Teaching percentile application questions, according to the following three levels from shallow to deep, from simple to complex, step by step, step by step. The first and the second time: the percentage of definitions directly leads to three types of simple application questions, namely ① seeking a number is another few percent of the number; ② seeking a few percent what is the number; ③ known a few hundred What is the number of points, seeking some number. Summarize alphabetically, that is, x% = b ÷ a, x = a × r%, and x = a ÷ r% (where x represents the number you want). (Example 1) Red Agricultural Machinery Plant The output value of the first quarter of this year was 250,000 yuan, the output value of the second quarter was 400,000 yuan. The third quarter output is the first