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在县“教学能手”评比活动中,连续听了多节数学课,其中一节课是“分数大小的比较”。练习时,老师出示了下面几组分数,让学生比较它们的大小。(1)4/5和5/6(2)5/7和8/(12)(3)7/(11)和9/(12)交流评议时,大部分学生都是采用通分的方法去比较,但有位学生却提出了一种新方法。他说:“先将前面分数的分子和后面分数的分母相乘,再将后面分数的分子和前面分数的分母相乘,然后比较积就可以知道分数的大小了。”并且还说这种方法是他瞎猜的,不知道对不对。授课的教师听后,先是愣了一下,然后说了句:“请你再仔细想一想。”就让学生坐下了,继续自己的教学。
In the County “teaching experts ” competition activities, continuous listening to multi-section math class, one of the class is “comparison of fractional size ”. When practicing, the teacher presents the following sets of scores so that students can compare their size. In the exchange of comments, most of the students adopted the method of passing points (1) 4/5 and 5/6 (2) 5/7 and 8 / (12) (3) 7 / (11) and 9 / (12) To compare, but one student has proposed a new method. He said: “First, multiply the numerator of the previous fraction by the denominator of the latter fraction, then multiply the numerator of the last fraction by the denominator of the previous fraction, and then compare the products to see the fractional fraction.” Kind of method is that he guessing, I do not know right or wrong. After listening to the lectures, the teacher froze for a moment and then said: “Please think again.” Let the students sit down and continue their teaching.