对有理数乘法法则生成课例的教学反思     

赵晓玲 《数学教学研究》2011,30(6):5-8

1问题的提出 《有理数乘法》属于《全日制义务教育数学课程标准（实验稿）》中的＂数与代数＂领域,是学生在学会有理数加法后学习的又一运算类型,它与有理数的加法运算一样,也是以小学算术为基础,即有理数的乘法运算在确定＂积＂的符号后,其实质就是小学数学中的乘法运算.  相似文献   

有理数新题“秀”     

罗文斌 《语数外学习(初中版七年级)》2011,(Z1):59

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鉴赏数字运算之美     

廖红菊  邱云华 《数学学习与研究(教研版)》2011,(3)

有很多看似不成立但正确的数学运算,可从中品味数字运算的乐趣,领悟数字运算的奇异美、秩序美和无限美,激发兴趣.  相似文献   

提高数学解答题运算准确性的方法     

李世桂 《高中数理化》2011,(13):18-20

近年来高考数学对运算能力的要求越来越高,有的同学因为运算准确率低而使得分偏低;有的同学因为运算方法不当,致使解题困难重重;有的同学因为运算速度慢,经常时间不够用,会做的题目来不及做,使其与高分失之交臂．本文就来谈谈提高解答题运算准确性的一些方法．  相似文献   

集合问题的解题策略     

刘冰 《数理化学习(高中版)》2011,(17)

有些集合问题,直接考虑并不易解决,如果改变考虑问题的角度,就可以把问题合理转化,得到简单易行的解法.下面介绍几例.一、灵活应用补集思想解题有些集合问题,从正面处理较难,一是解题思路不明朗,二是需要考虑的因素太多,要分多种情况讨论,运算量大,且讨论不全又容易出错.如用补集思想考虑其对立面,可以达到化繁为简的目的.  相似文献   

善用几何性质解决二次曲线问题     

潘新峰 《数学学习与研究(教研版)》2011,(5)

笔者发现,很多学生解决二次曲线问题时,常忽视对图形几何性质的研究,从而陷入繁杂的代数运算当中,即只着重数,而忽视形,不能真正实现数与形的结合.从数学解题追求解法简捷和思维优化的角度看,对学生能力的发展是不利的.限于篇幅,仅举以下几例,希望一线师生能从中得到一些启示.  相似文献   

“学生算错,‘我’的责任”——由“三位数乘两位数”计算错因分析引发的思考     

吴欣 《小学教学参考》2011,(4):10-10

运算能力是一个人最基本的数学能力之一。《数学课程标准》要求学生＂掌握必要的运算技能＂。随着课程改革的深入实施,学生的创造性思维、发散性思维得到了长足的发展,但不可否认的是学生的运算能力反而削弱了,为什么会这样？本文拟就＂三位数乘两位数＂计算错因分析,从教师的角度谈谈自己的思考。  相似文献   

一“语”激起千层浪     

刘红 《小学教学参考》2011,(23)

在课堂中,往往因为教师独具匠心的设计或者不经意间的一句问话,收到意想不到的效果。案例一:引导知识再创造如教学加法运算律时,课前,我认为学生从一年级开始就接触加法计算,对加法积累了较多的感性认识,有了这样的  相似文献   

FARMER: A novel approach to file access correlation mining and evaluation reference model     

夏鹏  冯丹  王芳 《上海大学学报(英文版)》2011,15(6):574-588

File semantic has proven effective in optimizing large scale distributed file system. As a consequence of the elaborate and rich I/O interfaces between upper layer applications and file systems, file system can provide useful and insightful information about semantic. Hence, file semantic mining has become an increasingly important practice in both engineering and research community. Unfortunately, it is a challenge to exploit file semantic knowledge because a variety of factors could affect this information exploration process. Even worse, the challenges are exacerbated due to the intricate interdependency between these factors, and make it difficult to fully exploit the potentially important correlation among various semantic knowledges. This article proposes a file access correlation miming and evaluation reference (FARMER) model, where file is treated as a multivariate vector space, and each item within the vector corresponds a separate factor of the given file. The selection of factor depends on the application, examples of factors are file path, creator and executing program. If one particular factor occurs in both files, its value is non-zero. It is clear that the extent of inter-file relationships can be measured based on the likeness of their factor values in the semantic vectors. Benefit from this model, FARMER represents files as structured vectors of identifiers, and basic vector operations can be leveraged to quantify file correlation between two file vectors. FARMER model leverages linear regression model to estimate the strength of the relationship between file correlation and a set of influencing factors so that the “bad knowledge” can be filtered out. To demonstrate the ability of new FARMER model, FARMER is incorporated into a real large-scale object-based storage system as a case study to dynamically infer file correlations. In addition FARMER-enabled optimize service for metadata prefetching algorithm and object data layout algorithm is implemented. Experimental results show that is FARMER-enabled prefetching algorithm is shown to reduce the metadata operations latency by approximately 30%–40% when compared to a state-of-the-art metadata prefetching algorithm and a commonly used replacement policy.  相似文献   

小学阶段如何开展有效的计算教学     

余贤发 《小学阅读指南(3-6年级)》2011,(11):47-47

新课改以来,我们在看到了数学课堂内发生喜人变化的同时也看到了另外一种现象：由于课改后对计算教学的目标进行了适当调整,降低了计算教学的要求,因此,学生进行计算练习的量少了,学生的计算能力下降了,具体表现为计算的正确率下降、口算速度变慢、简便运算方法不够灵活等等。针对这种情况,我们应清醒地反思自己的教学,每个年段都必须重视计算教学,避免使计算教学偏离课标要求。  相似文献