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1、状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,R五年级下册,单元重点知识归纳与易错总结,单元重点知识归纳,面,棱：面与面相交的线段,顶点：棱和棱的交点,长方体和正方体的认识,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元
2、成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,相交于一个顶点的三条棱的长度分别叫做长方体的长、宽、高。,长,高,宽,正方体可以看成是长、宽、高都相等的长方体。我们可以用下图来表示长方体和正方体的关系。,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元
3、成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,6个,12条,8个,6个,12条,8个,相对的4条棱的长度相等,12条棱的长度都相等,6个长方形（或有2个正方形和4个长方形）,6个完全相同的正方形,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路
4、,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,长方体表面积（长宽长高宽高）2,S2（abahbh）,长方体和正方体的表面积,正方体表面积棱长棱长6,S6a2,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,物体所占空间的大小叫做物体的体积。,1cm3,1dm3
5、,1m3,长方体的体积长宽高,Va b h,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,正方体的体积棱长棱长棱长,Va a a,正方体的体积公式一般写成: Va3,长方体（或正方体）的体积=底面积高,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,
6、状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,箱子、油桶、仓库等所能容纳物体的体积，通常叫做它们的容积。,1L=1000mL,1L1dm3,1mL1cm3,求不规则物体的体积,两次的体积差就是不规则物体的体积。,把不规则的物体转化为规则的。,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才
7、路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,没有正确理解长方体的特征。,【例题1】 判断：长方体的6个面一定都是长方形。（ ）,错误答案：,正确答案：,易错知识点总结,易错点1,错点警示：本题错在没有正确理解长方体的特征。长方体的6个面大多数情况下都是长方形，但是也有2个相对的面是正方形的长方体。 规避策略：长方体的6个面有时不都是长方形，有的长方体中有2个相对的面是正方形。,状元成才路,状元成才路,状元成才
8、路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,【例题2】一个长方体形状的无盖水桶，长4dm、宽3dm、高5dm，制作这个水桶至少需要铁皮多少平方分米？,错误答案：（43+53+45）=94（dm2）,正确答案：43+452+352=82（dm2）,没有根据实际情况求长方体的表面积。,易错点2,错点警示：本题错在审题不
9、仔细。水桶是没有盖的，也就是少一个上面，计算表面积时应少算一个43，而此题计算时却算了2个43。规避策略：在求长方体或正方体物体的表面积时，并不是所有的物体都有6个面，有的物体可能少1个面或2个面，要根据实际情况计算。,【例题3】判断：棱长是6cm的正方体，体积和表面积相等。（ ）,错误答案：,正确答案：,易错点3,没有掌握体积和表面积是不能比较的。,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成
10、才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,错点警示：本题错在只看计算结果的数据，没看数据的单位。体积是216cm3，表面积是216cm2，两者表示的意义不同，不能比较。,规避策略：体积和表面积不是同类量，两者之间不能比较。,【例题4】一个长方体的鱼缸，从里面量长是30cm，宽是20cm，高是18cm，里面的水高10cm，小东放入10条金鱼后，水面上升到11cm，这10条金鱼的体积是多少立方厘米？,求不规则物体的体积时，不能正确理解题意。,易错点4,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元
11、成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,错误答案：3020116600（cm3）答：这10条金鱼的体积是6600cm3。,正确答案：3020（1110）600（cm3）答：这10条金鱼的体积是600cm3。,错点警示：本题错在没有正确理解题意，放入金鱼后，水上升的高度并不是11cm，而是（1110）cm，这部分上升的水的体积才是金鱼的体积。规避策略：用“
12、排水法”求形状不规则的物体的体积时，将物体放入水中后，明确水上升的高度才是解题关键。,1.我会填。 （1）一个正方体的棱长总和是48cm，这个正方体的表面积是（ ）cm2，体积是（ ）cm3。 （2）一块正方体木料，它的底面积是9cm2，把它沿截面截成3个长方体，表面积增加了（ ）cm2。,96,64,36,单元复习训练,（3）一个长方体体积是480cm3，底面积是0.4dm2，高是（ ）cm。,12,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状
13、元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,2.一个游泳池长30m，宽15m，深20dm。 （1）在游泳池的四周和底部抹上水泥， 求抹水泥部分的面积。 （2）现在游泳池中注满了水，如果要使池中水深1.2m，要放多少升的水？,（1）20dm2m3015（302152）2450902450180630(m2)答：抹水泥部分的面积是630m2。,（2）20dm2m21.20.8（m）30150.8360（m3）360000dm3360000（L）答：要放360000L的水。,状元
14、成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,3.把一个棱长为6dm的正方体钢坯锻造成宽2.5dm，高1.6dm的长方体钢块。这个长方体钢块长多少分米？,666216（dm3）2162.51.654（dm）答：这个长方体钢块长54dm。,声 明本文件仅用于个人学习、研究或欣赏，以及其他非商业性或非盈利性用途，但同时应遵守著作权法及其他相关法律的规定，不得侵犯本司及相关权利人的合法权利。除此以外，将本文件任何内容用于其他用途时，应获得授权，如发现未经授权用于商业或盈利用途将追加侵权者的法律责任。武汉天成贵龙文化传播有限公司湖北山河律师事务所,