华琴的博客
    我已出发,向着梦的那方
频道栏目

查询

标题 作者


最新图库
暂未添加该信息。

博客统计
  • 今日数:0
  • 文章数:580
  • 收藏数:0
  • 图片数:0
  • 评论数:562
  • 开设时间:2009-10-29
  • 更新时间:2018-9-5

  • 最新链接
    暂未添加该信息。


    订阅本站的 RSS 2.0 新闻组


    华琴主页 >> 文章 >> 教后反思 >> 浏览信息《适度拓展,提升练习效果》

    教后反思 | 评论(1) | 阅读(1152)
    查看详细访友列表 访友脚印

    星期三   多云 
    主题 适度拓展,提升练习效果

    适度拓展,提升练习效果

     

    六下练习一第5题一共包括3道题目,为更有利于学生比较异同,发现规律,我把3道题目的出示顺序作了如下调整:

     

    1)小红身高135厘米,小娟身高150厘米。小娟的身高是小红的百分之几?

     

    2)小红身高135厘米,小娟比小红高15厘米。小娟的身高是小红的百分之几?

     

    3)小红身高135厘米,小娟身高150厘米。小娟的身高比小红高百分之几?

     

    在学生独立解答(1)和(2)以后,及时组织学生比较这两题的异同。相同点是所求问题相同,都是求“小娟的身高是小红的百分之几?”;不同点是已知条件不同。还有没有不同之处呢?经过适当提示,学生说出两题的解题过程也不同。问题(2)比问题(1)多算一步,必须先算出小娟的身高,再用小娟的身高除以小红的身高。

     

    在比较异同的过程中,让学生进一步体会到已知条件的不同,导致已知条件和要求问题的组合方式不同,使得问题求解的步骤多少不同。在平时的解题练习中,向学生强化审题习惯的教育和培养。

     

    第(3)题照例先让学生独立列式解答。学生因受五下百分数实际问题解题方法的影响,普遍都选择先算小娟比小红高多少厘米,再算小娟的身高比小红高百分之几。这种解法列综合算式是:(150-135)÷135

     

    为进一步丰富学生的解答方法,完善学生的认知结构,我希望学生能够像掌握第一种解法一样喜欢第二种解法,于是询问学生:第(3)题还有没有其他解法?部分学生会。我根据学生的口答板书:150÷135-100%,并请学生详细解释先算哪部分,求出什么,再算哪部分,求出什么。经过详细的分解,唤起了学生关于此种解法的回忆,知道了“求一个数比另一个数多(或少)百分之几的实际问题”,既可以先算两种数量的差,再用差除以单位“1”的量;也可以先算一个数除以单位“1”的量,再与100%比较:若比100%大,则减去100%,若比100%小,则用100%减去这个百分数。

     

    细心的同学通过观察比较两个综合算式,还发现这两种解法都包括除法和减法两种运算,不过是一种方法先算减法再算除法,另一种方法先算除法再算减法。

     

    经过如此细致的分解,对习题进行适度的拓展,学生不仅理解并掌握了解题的不同方法,还理清了两种不同方法之间的本质联系,使知识由“点状”成为“块状”,更便于纳入已有认知结构,便于学生的后续学习。

     

    华琴 发表于:2011-2-16 10:00:07

    评论 

    One of the largest decisions that wig wearers ought to build is whether or not they need to possess an individual's or artificial ones. Obviously, there’s nothing wrong with having each, however Gatlin says it’s vital to understand the benefits and drawbacks of every.While a high quality human hair wig won’t be low-cost, and can need an equivalent daily maintenance of your real hair and may react to weather (frizz, loss of curls), it’s additionally additional versatile and tangle-free. On the contrary, an artificial wig is typically more cost-effective and needs very little to no maintenance. At an equivalent time, you’re sacrificing skillfulness and can most likely got to replace additional typically than an individual's one.Both designs are often created into a lacefront, that is best delineate as a wig with a mesh hairline. Gatlin says, “The mesh or ‘lace’ ought to have neutral tone that may mix with the skin tone and appears invisible once applied to your hairline.Again, your selection is basically a matter of preference and modus vivendi, 2 stuff you ought to contemplate before shopping for. As somebody World Health Organization is consistently on-the-go and customarily lazy together with her hair routine, I fell taken with with my micro-twist wig as a result of I may throw it on and run out the door in no time.The Greek deity Air Georgia home boy 90/1 could be a new hybrid vogue that 1st born within the OG University Red colorway. The sneaker simply created its debut overseas in another OG theme of optical device Blue this August. The sneaker’s Air Georgia home boy one higher is roofed in white mesh and contrastive animal skin overlays in black and light-weight gray for the Swooshes, whereas the pop of optical device blue is value-added on the tongue disapproval, higher eyelets, and exterior of the visible Air Georgia home boy padding. Finally, a white rubber sole crack it all off.Retailing for $140, explore for the Greek deity Air Georgia home boy 90/1 optical device Blue at Greek deity stores overseas these days, however a stateside drop is returning presently. continuously keep it bolted to KicksOnFire for the most recent in sneaker news, unharness dates and wherever to get your favorite kicks.human hair wigscheap lace front wigsfull lace wigslace front wigshuman hair lace front wigssynthetic wigswigs for womencheap human hair wigscheap synthetic wigscheap wigs for womencheap bob wigsafrican american wigs cheapafro wigs cheapcheap full lace wigscheap curly wigscheap cosplay wigscheap wigs for mencheap costume wigscheap hair extensionscheap nike shoes nike air maxnike air max 90 roshe run women roshe run mennike force 1nike air max 90 womens white white roshes mens roshes women cheap air max 90 air max 270 mens nike air max 1 mens cheap nikes online nike sb janoski nike skateboarding shoes nike air force one men nike air force 1 low black huaraches nike huarache womenair max 270  air max sale nike air max saleair jordan 4
    码确 发表于:2018-9-5 22:05:40