【2020新】北师大版四年级数学下册《15街心广场》课件

1、 街心广场 （建议一课时完成）第三单元 小数乘法 四年级下册 课后作业探索新知积的小数位数与乘数的小数位数的关系1课堂探究点2课时流程课堂小结当堂检测北师大版四年级数学下册20米30米北师大版四年级数学下册探究点 积的小数位数与乘数的小数位数的关系先说一说街心广场上的数学信息，再算一算，填一填。街心广场花坛地砖面积/平方米北师大版四年级数学下册淘气在计算地砖的面积时遇到了困难，你能帮帮他吗？0.30.2 （ ）0.3米3分米0.2米2分米326（平方分米）6平方分米0.06（平方米）6（平方米）0.3米0.2米321米1米0.01平方米6个0.01是0.06平方米。0.06

2、平方米北师大版四年级数学下册结合上面的计算过程，想一想乘数和积之间有什么关系。30 206003 2 6北师大版四年级数学下册积的小数位数与乘数的小数位数有什么关系？算一算，想一想。0.10.30.1320.130.2第一个乘数的小数位数第二个乘数的小数位数积的小数位数0.260.026011112202213北师大版四年级数学下册小试牛刀（源于典中点）1算一算。(1)10101000. 1 8北师大版四年级数学下册(2)北师大版四年级数学下册2填一填。(1)一个乘数扩大到原来的10倍，另一个乘数扩大到原来的100倍，积就扩大到原来的( )倍。(2)一

3、个乘数缩小到原来的 ，另一个乘数也缩小到原来的 ，积就缩小到原来的()。1000北师大版四年级数学下册3把表格补充完整，你发现了什么？我发现：_。算式第一个乘数的小数位数第二个乘数的小数位数积的小数位数0.0330.090.20.28202001112两个乘数一共有几位小数，积就有几位小数(答案不唯一)北师大版四年级数学下册4根据第一栏的积快速写出后面每栏的积。乘数12121.21.2121201.2乘数1515050.15积1801800181.818180.18北师大版四年级数学下册归纳总结：（讲解源于典中点）两个数相乘，每一个乘数都乘(或除以)一

4、个不为0的数，它们的积就乘(或除以)这两个不为0的数的乘积。北师大版四年级数学下册小试牛刀（教材P39练一练）你会计算这块拼图的面积吗？想一想，算一算。 （1）与同伴交流你的想法。 （2）结合计算过程说一说，积的 小数位数与乘数的小数位数 有什么关系？略。9(平方米)积的小数位数是乘数的小数位数之和。北师大版四年级数学下册根据第一栏的积很快写出后面每栏的积。乘数363.6363.60.36乘数242.42.4242.4积8648.6486.486.40.864北师大版四年级数学下册淘气的计算器上的小数点无法显示了，你能帮他得到正确答案吗？北师大版四年级数学下册明明每天上学和放

5、学都要乘坐一次公交车，每乘一次公交车花0.2元。明明的公交卡里还剩3元，够他一周5天上学和放学用吗？0.220.4（元）0.452（元）够他一周5天上学和放学用。根据1312156，在 里填上适当的数。13 1.2 1.3 1.21.312 13 2 1.31200.13 1.2 130 1.2点拨：答案不唯一。易错辨析5判断。(对的画“”，错的画“”)(1)2.45的积的小数位数有0位。()(2)0.1258的积有三位小数。()辨析：两个乘数一个共有几位小数，积就有几位小数。版权申明本文部分内容，包括文字、图片、以及设计等在网上搜集整理.版权为个人所有This artic

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